diff --git a/openedx/core/djangoapps/content/search/api.py b/openedx/core/djangoapps/content/search/api.py
index d81128f65950..389f6d21161f 100644
--- a/openedx/core/djangoapps/content/search/api.py
+++ b/openedx/core/djangoapps/content/search/api.py
@@ -51,8 +51,7 @@
     searchable_doc_for_library_block,
     searchable_doc_for_key,
     searchable_doc_tags,
-    searchable_doc_tags_for_collection,
-    searchable_doc_units,
+    searchable_doc_containers,
 )
 
 log = logging.getLogger(__name__)
@@ -452,7 +451,7 @@ def index_library(lib_key: LibraryLocatorV2) -> list:
                     doc.update(searchable_doc_for_library_block(metadata))
                     doc.update(searchable_doc_tags(metadata.usage_key))
                     doc.update(searchable_doc_collections(metadata.usage_key))
-                    doc.update(searchable_doc_units(metadata.usage_key))
+                    doc.update(searchable_doc_containers(metadata.usage_key, "units"))
                     docs.append(doc)
                 except Exception as err:  # pylint: disable=broad-except
                     status_cb(f"Error indexing library component {component}: {err}")
@@ -471,7 +470,7 @@ def index_collection_batch(batch, num_done, library_key) -> int:
                 try:
                     collection_key = lib_api.library_collection_locator(library_key, collection.key)
                     doc = searchable_doc_for_collection(collection_key, collection=collection)
-                    doc.update(searchable_doc_tags_for_collection(collection_key))
+                    doc.update(searchable_doc_tags(collection_key))
                     docs.append(doc)
                 except Exception as err:  # pylint: disable=broad-except
                     status_cb(f"Error indexing collection {collection}: {err}")
@@ -497,6 +496,12 @@ def index_container_batch(batch, num_done, library_key) -> int:
                     doc = searchable_doc_for_container(container_key)
                     doc.update(searchable_doc_tags(container_key))
                     doc.update(searchable_doc_collections(container_key))
+                    container_type = lib_api.ContainerType(container_key.container_type)
+                    match container_type:
+                        case lib_api.ContainerType.Unit:
+                            doc.update(searchable_doc_containers(container_key, "subsections"))
+                        case lib_api.ContainerType.Subsection:
+                            doc.update(searchable_doc_containers(container_key, "sections"))
                     docs.append(doc)
                 except Exception as err:  # pylint: disable=broad-except
                     status_cb(f"Error indexing container {container.key}: {err}")
@@ -696,7 +701,7 @@ def upsert_library_collection_index_doc(collection_key: LibraryCollectionLocator
     If the Collection is not found or disabled (i.e. soft-deleted), then delete it from the search index.
     """
     doc = searchable_doc_for_collection(collection_key)
-    update_components = False
+    update_items = False
 
     # Soft-deleted/disabled collections are removed from the index
     # and their components updated.
@@ -755,7 +760,8 @@ def update_library_components_collections(
                 library_key,
                 component,
             )
-            doc = searchable_doc_collections(usage_key)
+            doc = searchable_doc_for_key(usage_key)
+            doc.update(searchable_doc_collections(usage_key))
             docs.append(doc)
 
         log.info(
@@ -790,7 +796,8 @@ def update_library_containers_collections(
                 library_key,
                 container,
             )
-            doc = searchable_doc_collections(container_key)
+            doc = searchable_doc_for_key(container_key)
+            doc.update(searchable_doc_collections(container_key))
             docs.append(doc)
 
         log.info(
@@ -855,21 +862,12 @@ def upsert_item_collections_index_docs(opaque_key: OpaqueKey):
     _update_index_docs([doc])
 
 
-def upsert_item_units_index_docs(opaque_key: OpaqueKey):
+def upsert_item_containers_index_docs(opaque_key: OpaqueKey, container_type: str):
     """
-    Updates the units data in documents for the given Course/Library block
+    Updates the containers (units/subsections/sections) data in documents for the given Course/Library block
     """
     doc = {Fields.id: meili_id_from_opaque_key(opaque_key)}
-    doc.update(searchable_doc_units(opaque_key))
-    _update_index_docs([doc])
-
-
-def upsert_collection_tags_index_docs(collection_key: LibraryCollectionLocator):
-    """
-    Updates the tags data in documents for the given library collection
-    """
-
-    doc = searchable_doc_tags_for_collection(collection_key)
+    doc.update(searchable_doc_containers(opaque_key, container_type))
     _update_index_docs([doc])
 
 
diff --git a/openedx/core/djangoapps/content/search/documents.py b/openedx/core/djangoapps/content/search/documents.py
index 34a3c86b375e..aaabb0b92a51 100644
--- a/openedx/core/djangoapps/content/search/documents.py
+++ b/openedx/core/djangoapps/content/search/documents.py
@@ -67,10 +67,15 @@ class Fields:
     collections = "collections"
     collections_display_name = "display_name"
     collections_key = "key"
-    # Units (dictionary) that this object belongs to.
+    # Containers (dictionaries) that this object belongs to.
     units = "units"
-    units_display_name = "display_name"
-    units_key = "key"
+    subsections = "subsections"
+    sections = "sections"
+    containers_display_name = "display_name"
+    containers_key = "key"
+
+    sections_display_name = "display_name"
+    sections_key = "key"
 
     # The "content" field is a dictionary of arbitrary data, depending on the block_type.
     # It comes from each XBlock's index_dictionary() method (if present) plus some processing.
@@ -97,6 +102,8 @@ class Fields:
 
     # List of children keys
     child_usage_keys = "child_usage_keys"
+    # List of children display names
+    child_display_names = "child_display_names"
 
     # Note: new fields or values can be added at any time, but if they need to be indexed for filtering or keyword
     # search, the index configuration will need to be changed, which is only done as part of the 'reindex_studio'
@@ -255,7 +262,92 @@ class implementation returns only:
     return block_data
 
 
-def _tags_for_content_object(object_id: OpaqueKey) -> dict:
+def _published_data_from_block(block_published) -> dict:
+    """
+    Given an library block get the published data.
+    """
+    result = {
+        Fields.published: {
+            Fields.published_display_name: xblock_api.get_block_display_name(block_published),
+        }
+    }
+
+    try:
+        content_data = _get_content_from_block(block_published)
+
+        description = _get_description_from_block_content(
+            block_published.scope_ids.block_type,
+            content_data,
+        )
+
+        if description:
+            result[Fields.published][Fields.published_description] = description
+    except Exception as err:  # pylint: disable=broad-except
+        log.exception(f"Failed to process index_dictionary for {block_published.usage_key}: {err}")
+
+    return result
+
+
+def searchable_doc_for_library_block(xblock_metadata: lib_api.LibraryXBlockMetadata) -> dict:
+    """
+    Generate a dictionary document suitable for ingestion into a search engine
+    like Meilisearch or Elasticsearch, so that the given library block can be
+    found using faceted search.
+
+    Datetime fields (created, modified, last_published) are serialized to POSIX timestamps so that they can be used to
+    sort the search results.
+    """
+    library_name = lib_api.get_library(xblock_metadata.usage_key.context_key).title
+    block = xblock_api.load_block(xblock_metadata.usage_key, user=None)
+
+    publish_status = PublishStatus.published
+    try:
+        block_published = xblock_api.load_block(xblock_metadata.usage_key, user=None, version=LatestVersion.PUBLISHED)
+        if xblock_metadata.last_published and xblock_metadata.last_published < xblock_metadata.modified:
+            publish_status = PublishStatus.modified
+    except NotFound:
+        # Never published
+        block_published = None
+        publish_status = PublishStatus.never
+
+    doc = searchable_doc_for_key(xblock_metadata.usage_key)
+    doc.update({
+        Fields.type: DocType.library_block,
+        Fields.breadcrumbs: [],
+        Fields.created: xblock_metadata.created.timestamp(),
+        Fields.modified: xblock_metadata.modified.timestamp(),
+        Fields.last_published: xblock_metadata.last_published.timestamp() if xblock_metadata.last_published else None,
+        Fields.publish_status: publish_status,
+    })
+
+    doc.update(_fields_from_block(block))
+
+    if block_published:
+        doc.update(_published_data_from_block(block_published))
+
+    # Add the breadcrumbs. In v2 libraries, the library itself is not a "parent" of the XBlocks so we add it here:
+    doc[Fields.breadcrumbs] = [{"display_name": library_name}]
+
+    return doc
+
+
+def searchable_doc_for_course_block(block) -> dict:
+    """
+    Generate a dictionary document suitable for ingestion into a search engine
+    like Meilisearch or Elasticsearch, so that the given course block can be
+    found using faceted search.
+    """
+    doc = searchable_doc_for_key(block.usage_key)
+    doc.update({
+        Fields.type: DocType.course_block,
+    })
+
+    doc.update(_fields_from_block(block))
+
+    return doc
+
+
+def searchable_doc_tags(object_id: OpaqueKey) -> dict:
     """
     Given an XBlock, course, library, etc., get the tag data for its index doc.
 
@@ -320,7 +412,7 @@ def _tags_for_content_object(object_id: OpaqueKey) -> dict:
     return {Fields.tags: result}
 
 
-def _collections_for_content_object(object_id: OpaqueKey) -> dict:
+def searchable_doc_collections(object_id: OpaqueKey) -> dict:
     """
     Given an XBlock, course, library, etc., get the collections for its index doc.
 
@@ -376,9 +468,9 @@ def _collections_for_content_object(object_id: OpaqueKey) -> dict:
     return result
 
 
-def _units_for_content_object(object_id: OpaqueKey) -> dict:
+def searchable_doc_containers(object_id: OpaqueKey, container_type: str) -> dict:
     """
-    Given an XBlock, course, library, etc., get the units for its index doc.
+    Given an XBlock, course, library, etc., get the containers that it is part of for its index doc.
 
     e.g. for something in Units "UNIT_A" and "UNIT_B", this would return:
         {
@@ -388,173 +480,43 @@ def _units_for_content_object(object_id: OpaqueKey) -> dict:
             }
         }
 
-    If the object is in no collections, returns:
+    If the object is in no containers, returns:
         {
-            "collections":  {
+            "sections":  {
                 "display_name": [],
                 "key": [],
             },
         }
     """
+    container_field = getattr(Fields, container_type)
     result = {
-        Fields.units: {
-            Fields.units_display_name: [],
-            Fields.units_key: [],
+        container_field: {
+            Fields.containers_display_name: [],
+            Fields.containers_key: [],
         }
     }
 
     # Gather the units associated with this object
-    units = None
+    containers = None
     try:
-        if isinstance(object_id, UsageKey):
-            units = lib_api.get_containers_contains_component(object_id)
+        if isinstance(object_id, OpaqueKey):
+            containers = lib_api.get_containers_contains_item(object_id)
         else:
             log.warning(f"Unexpected key type for {object_id}")
 
     except ObjectDoesNotExist:
         log.warning(f"No library item found for {object_id}")
 
-    if not units:
+    if not containers:
         return result
 
-    for unit in units:
-        result[Fields.units][Fields.units_display_name].append(unit.display_name)
-        result[Fields.units][Fields.units_key].append(str(unit.container_key))
+    for container in containers:
+        result[container_field][Fields.containers_display_name].append(container.display_name)
+        result[container_field][Fields.containers_key].append(str(container.container_key))
 
     return result
 
 
-def _published_data_from_block(block_published) -> dict:
-    """
-    Given an library block get the published data.
-    """
-    result = {
-        Fields.published: {
-            Fields.published_display_name: xblock_api.get_block_display_name(block_published),
-        }
-    }
-
-    try:
-        content_data = _get_content_from_block(block_published)
-
-        description = _get_description_from_block_content(
-            block_published.scope_ids.block_type,
-            content_data,
-        )
-
-        if description:
-            result[Fields.published][Fields.published_description] = description
-    except Exception as err:  # pylint: disable=broad-except
-        log.exception(f"Failed to process index_dictionary for {block_published.usage_key}: {err}")
-
-    return result
-
-
-def searchable_doc_for_library_block(xblock_metadata: lib_api.LibraryXBlockMetadata) -> dict:
-    """
-    Generate a dictionary document suitable for ingestion into a search engine
-    like Meilisearch or Elasticsearch, so that the given library block can be
-    found using faceted search.
-
-    Datetime fields (created, modified, last_published) are serialized to POSIX timestamps so that they can be used to
-    sort the search results.
-    """
-    library_name = lib_api.get_library(xblock_metadata.usage_key.context_key).title
-    block = xblock_api.load_block(xblock_metadata.usage_key, user=None)
-
-    publish_status = PublishStatus.published
-    try:
-        block_published = xblock_api.load_block(xblock_metadata.usage_key, user=None, version=LatestVersion.PUBLISHED)
-        if xblock_metadata.last_published and xblock_metadata.last_published < xblock_metadata.modified:
-            publish_status = PublishStatus.modified
-    except NotFound:
-        # Never published
-        block_published = None
-        publish_status = PublishStatus.never
-
-    doc = searchable_doc_for_key(xblock_metadata.usage_key)
-    doc.update({
-        Fields.type: DocType.library_block,
-        Fields.breadcrumbs: [],
-        Fields.created: xblock_metadata.created.timestamp(),
-        Fields.modified: xblock_metadata.modified.timestamp(),
-        Fields.last_published: xblock_metadata.last_published.timestamp() if xblock_metadata.last_published else None,
-        Fields.publish_status: publish_status,
-    })
-
-    doc.update(_fields_from_block(block))
-
-    if block_published:
-        doc.update(_published_data_from_block(block_published))
-
-    # Add the breadcrumbs. In v2 libraries, the library itself is not a "parent" of the XBlocks so we add it here:
-    doc[Fields.breadcrumbs] = [{"display_name": library_name}]
-
-    return doc
-
-
-def searchable_doc_tags(key: OpaqueKey) -> dict:
-    """
-    Generate a dictionary document suitable for ingestion into a search engine
-    like Meilisearch or Elasticsearch, with the tags data for the given content object.
-    """
-    doc = searchable_doc_for_key(key)
-    doc.update(_tags_for_content_object(key))
-
-    return doc
-
-
-def searchable_doc_collections(opaque_key: OpaqueKey) -> dict:
-    """
-    Generate a dictionary document suitable for ingestion into a search engine
-    like Meilisearch or Elasticsearch, with the collections data for the given content object.
-    """
-    doc = searchable_doc_for_key(opaque_key)
-    doc.update(_collections_for_content_object(opaque_key))
-
-    return doc
-
-
-def searchable_doc_units(opaque_key: OpaqueKey) -> dict:
-    """
-    Generate a dictionary document suitable for ingestion into a search engine
-    like Meilisearch or Elasticsearch, with the units data for the given content object.
-    """
-    doc = searchable_doc_for_key(opaque_key)
-    doc.update(_units_for_content_object(opaque_key))
-
-    return doc
-
-
-def searchable_doc_tags_for_collection(
-    collection_key: LibraryCollectionLocator
-) -> dict:
-    """
-    Generate a dictionary document suitable for ingestion into a search engine
-    like Meilisearch or Elasticsearch, with the tags data for the given library collection.
-    """
-    doc = searchable_doc_for_key(collection_key)
-    doc.update(_tags_for_content_object(collection_key))
-
-    return doc
-
-
-def searchable_doc_for_course_block(block) -> dict:
-    """
-    Generate a dictionary document suitable for ingestion into a search engine
-    like Meilisearch or Elasticsearch, so that the given course block can be
-    found using faceted search.
-    """
-    doc = searchable_doc_for_key(block.usage_key)
-    doc.update({
-        Fields.type: DocType.course_block,
-    })
-
-    doc.update(_fields_from_block(block))
-
-    return doc
-
-
 def searchable_doc_for_collection(
     collection_key: LibraryCollectionLocator,
     *,
@@ -674,13 +636,17 @@ def get_child_keys(children) -> list[str]:
                     for child in children
                 ]
 
+    def get_child_names(children) -> list[str]:
+        return [child.display_name for child in children]
+
     doc.update({
         Fields.display_name: container.display_name,
         Fields.created: container.created.timestamp(),
         Fields.modified: container.modified.timestamp(),
         Fields.num_children: len(draft_children),
         Fields.content: {
-            Fields.child_usage_keys: get_child_keys(draft_children)
+            Fields.child_usage_keys: get_child_keys(draft_children),
+            Fields.child_display_names: get_child_names(draft_children),
         },
         Fields.publish_status: publish_status,
         Fields.last_published: container.last_published.timestamp() if container.last_published else None,
@@ -699,6 +665,7 @@ def get_child_keys(children) -> list[str]:
             Fields.published_num_children: len(published_children),
             Fields.published_content: {
                 Fields.child_usage_keys: get_child_keys(published_children),
+                Fields.child_display_names: get_child_names(published_children),
             },
         }
 
diff --git a/openedx/core/djangoapps/content/search/handlers.py b/openedx/core/djangoapps/content/search/handlers.py
index fdc52a968e5e..1b0f3f199616 100644
--- a/openedx/core/djangoapps/content/search/handlers.py
+++ b/openedx/core/djangoapps/content/search/handlers.py
@@ -44,9 +44,8 @@
 from .api import (
     only_if_meilisearch_enabled,
     upsert_content_object_tags_index_doc,
-    upsert_collection_tags_index_docs,
     upsert_item_collections_index_docs,
-    upsert_item_units_index_docs,
+    upsert_item_containers_index_docs,
 )
 from .tasks import (
     delete_library_block_index_doc,
@@ -258,14 +257,15 @@ def content_object_associations_changed_handler(**kwargs) -> None:
     # This event's changes may contain both "tags" and "collections", but this will happen rarely, if ever.
     # So we allow a potential double "upsert" here.
     if not content_object.changes or "tags" in content_object.changes:
-        if isinstance(opaque_key, LibraryCollectionLocator):
-            upsert_collection_tags_index_docs(opaque_key)
-        else:
-            upsert_content_object_tags_index_doc(opaque_key)
+        upsert_content_object_tags_index_doc(opaque_key)
     if not content_object.changes or "collections" in content_object.changes:
         upsert_item_collections_index_docs(opaque_key)
     if not content_object.changes or "units" in content_object.changes:
-        upsert_item_units_index_docs(opaque_key)
+        upsert_item_containers_index_docs(opaque_key, "units")
+    if not content_object.changes or "sections" in content_object.changes:
+        upsert_item_containers_index_docs(opaque_key, "sections")
+    if not content_object.changes or "subsections" in content_object.changes:
+        upsert_item_containers_index_docs(opaque_key, "subsections")
 
 
 @receiver(LIBRARY_CONTAINER_CREATED)
diff --git a/openedx/core/djangoapps/content/search/tests/test_api.py b/openedx/core/djangoapps/content/search/tests/test_api.py
index 3b22ce389d0f..b2b0cd17169a 100644
--- a/openedx/core/djangoapps/content/search/tests/test_api.py
+++ b/openedx/core/djangoapps/content/search/tests/test_api.py
@@ -256,7 +256,10 @@ def setUp(self) -> None:
             "display_name": "Unit 1",
             # description is not set for containers
             "num_children": 0,
-            "content": {"child_usage_keys": []},
+            "content": {
+                "child_usage_keys": [],
+                "child_display_names": [],
+            },
             "publish_status": "never",
             "context_key": "lib:org1:lib",
             "org": "org1",
@@ -276,7 +279,10 @@ def setUp(self) -> None:
             "display_name": "Subsection 1",
             # description is not set for containers
             "num_children": 0,
-            "content": {"child_usage_keys": []},
+            "content": {
+                "child_usage_keys": [],
+                "child_display_names": [],
+            },
             "publish_status": "never",
             "context_key": "lib:org1:lib",
             "org": "org1",
@@ -296,7 +302,10 @@ def setUp(self) -> None:
             "display_name": "Section 1",
             # description is not set for containers
             "num_children": 0,
-            "content": {"child_usage_keys": []},
+            "content": {
+                "child_usage_keys": [],
+                "child_display_names": [],
+            },
             "publish_status": "never",
             "context_key": "lib:org1:lib",
             "org": "org1",
@@ -336,9 +345,11 @@ def test_reindex_meilisearch(self, mock_meilisearch) -> None:
         doc_unit = copy.deepcopy(self.unit_dict)
         doc_unit["tags"] = {}
         doc_unit["collections"] = {'display_name': [], 'key': []}
+        doc_unit["subsections"] = {"display_name": [], "key": []}
         doc_subsection = copy.deepcopy(self.subsection_dict)
         doc_subsection["tags"] = {}
         doc_subsection["collections"] = {'display_name': [], 'key': []}
+        doc_subsection["sections"] = {'display_name': [], 'key': []}
         doc_section = copy.deepcopy(self.section_dict)
         doc_section["tags"] = {}
         doc_section["collections"] = {'display_name': [], 'key': []}
@@ -376,9 +387,11 @@ def test_reindex_meilisearch_incremental(self, mock_meilisearch) -> None:
         doc_unit = copy.deepcopy(self.unit_dict)
         doc_unit["tags"] = {}
         doc_unit["collections"] = {"display_name": [], "key": []}
+        doc_unit["subsections"] = {"display_name": [], "key": []}
         doc_subsection = copy.deepcopy(self.subsection_dict)
         doc_subsection["tags"] = {}
         doc_subsection["collections"] = {'display_name': [], 'key': []}
+        doc_subsection["sections"] = {'display_name': [], 'key': []}
         doc_section = copy.deepcopy(self.section_dict)
         doc_section["tags"] = {}
         doc_section["collections"] = {'display_name': [], 'key': []}
@@ -983,14 +996,21 @@ def test_delete_index_container(self, container_type, mock_meilisearch) -> None:
             container_dict["id"],
         )
 
+    @ddt.data(
+        "unit",
+        "subsection",
+        "section",
+    )
     @override_settings(MEILISEARCH_ENABLED=True)
-    def test_index_library_container_metadata(self, mock_meilisearch) -> None:
+    def test_index_library_container_metadata(self, container_type, mock_meilisearch) -> None:
         """
         Test indexing a Library Container.
         """
-        api.upsert_library_container_index_doc(self.unit.container_key)
+        container = getattr(self, container_type)
+        container_dict = getattr(self, f"{container_type}_dict")
+        api.upsert_library_container_index_doc(container.container_key)
 
-        mock_meilisearch.return_value.index.return_value.update_documents.assert_called_once_with([self.unit_dict])
+        mock_meilisearch.return_value.index.return_value.update_documents.assert_called_once_with([container_dict])
 
     @ddt.data(
         ("unit", "lctorg1libunitunit-1-e4527f7c"),
@@ -1050,7 +1070,10 @@ def test_block_in_units(self, mock_meilisearch) -> None:
         new_unit_dict = {
             **self.unit_dict,
             "num_children": 1,
-            'content': {'child_usage_keys': [self.doc_problem1["usage_key"]]}
+            'content': {
+                'child_usage_keys': [self.doc_problem1["usage_key"]],
+                'child_display_names': [self.doc_problem1["display_name"]],
+            }
         }
 
         assert mock_meilisearch.return_value.index.return_value.update_documents.call_count == 2
@@ -1071,16 +1094,25 @@ def test_units_in_subsection(self, mock_meilisearch) -> None:
                 None,
             )
 
-        # TODO verify subsections in units
-
+        doc_block_with_subsections = {
+            "id": self.unit_dict["id"],
+            "subsections": {
+                "display_name": [self.subsection.display_name],
+                "key": [self.subsection_key],
+            },
+        }
         new_subsection_dict = {
             **self.subsection_dict,
             "num_children": 1,
-            'content': {'child_usage_keys': [self.unit_key]}
+            'content': {
+                'child_usage_keys': [self.unit_key],
+                'child_display_names': [self.unit.display_name]
+            }
         }
-        assert mock_meilisearch.return_value.index.return_value.update_documents.call_count == 1
+        assert mock_meilisearch.return_value.index.return_value.update_documents.call_count == 2
         mock_meilisearch.return_value.index.return_value.update_documents.assert_has_calls(
             [
+                call([doc_block_with_subsections]),
                 call([new_subsection_dict]),
             ],
             any_order=True,
@@ -1095,16 +1127,25 @@ def test_section_in_usbsections(self, mock_meilisearch) -> None:
                 None,
             )
 
-        # TODO verify section in subsections
-
+        doc_block_with_sections = {
+            "id": self.subsection_dict["id"],
+            "sections": {
+                "display_name": [self.section.display_name],
+                "key": [self.section_key],
+            },
+        }
         new_section_dict = {
             **self.section_dict,
             "num_children": 1,
-            'content': {'child_usage_keys': [self.subsection_key]}
+            'content': {
+                'child_usage_keys': [self.subsection_key],
+                'child_display_names': [self.subsection.display_name],
+            }
         }
-        assert mock_meilisearch.return_value.index.return_value.update_documents.call_count == 1
+        assert mock_meilisearch.return_value.index.return_value.update_documents.call_count == 2
         mock_meilisearch.return_value.index.return_value.update_documents.assert_has_calls(
             [
+                call([doc_block_with_sections]),
                 call([new_section_dict]),
             ],
             any_order=True,
diff --git a/openedx/core/djangoapps/content/search/tests/test_documents.py b/openedx/core/djangoapps/content/search/tests/test_documents.py
index 0ff45fa53e9b..5a8a2231dcdd 100644
--- a/openedx/core/djangoapps/content/search/tests/test_documents.py
+++ b/openedx/core/djangoapps/content/search/tests/test_documents.py
@@ -26,13 +26,11 @@
         searchable_doc_for_course_block,
         searchable_doc_for_library_block,
         searchable_doc_tags,
-        searchable_doc_tags_for_collection,
     )
     from ..models import SearchAccess
 except RuntimeError:
     searchable_doc_for_course_block = lambda x: x
     searchable_doc_tags = lambda x: x
-    searchable_doc_tags_for_collection = lambda x: x
     searchable_doc_for_collection = lambda x: x
     searchable_doc_for_container = lambda x: x
     searchable_doc_for_library_block = lambda x: x
@@ -484,7 +482,7 @@ def test_html_published_library_block(self):
 
     def test_collection_with_library(self):
         doc = searchable_doc_for_collection(self.collection_key)
-        doc.update(searchable_doc_tags_for_collection(self.collection_key))
+        doc.update(searchable_doc_tags(self.collection_key))
 
         assert doc == {
             "id": "lib-collectionedx2012_falltoy_collection-d1d907a4",
@@ -513,7 +511,7 @@ def test_collection_with_published_library(self):
         library_api.publish_changes(self.library.key)
 
         doc = searchable_doc_for_collection(self.collection_key)
-        doc.update(searchable_doc_tags_for_collection(self.collection_key))
+        doc.update(searchable_doc_tags(self.collection_key))
 
         assert doc == {
             "id": "lib-collectionedx2012_falltoy_collection-d1d907a4",
@@ -564,6 +562,7 @@ def test_draft_container(self, container_name, container_slug, container_type, d
             "num_children": 0,
             "content": {
                 "child_usage_keys": [],
+                "child_display_names": [],
             },
             "publish_status": "never",
             "context_key": "lib:edX:2012_Fall",
@@ -609,6 +608,9 @@ def test_published_container(self):
                 "child_usage_keys": [
                     "lb:edX:2012_Fall:html:text2",
                 ],
+                "child_display_names": [
+                    "Text",
+                ],
             },
             "publish_status": "published",
             "context_key": "lib:edX:2012_Fall",
@@ -628,6 +630,9 @@ def test_published_container(self):
                     "child_usage_keys": [
                         "lb:edX:2012_Fall:html:text2",
                     ],
+                    "child_display_names": [
+                        "Text",
+                    ],
                 },
             },
         }
@@ -676,6 +681,10 @@ def test_published_container_with_changes(self):
                     "lb:edX:2012_Fall:html:text2",
                     "lb:edX:2012_Fall:html:text3",
                 ],
+                "child_display_names": [
+                    "Text",
+                    "Text",
+                ],
             },
             "publish_status": "modified",
             "context_key": "lib:edX:2012_Fall",
@@ -695,6 +704,9 @@ def test_published_container_with_changes(self):
                     "child_usage_keys": [
                         "lb:edX:2012_Fall:html:text2",
                     ],
+                    "child_display_names": [
+                        "Text",
+                    ],
                 },
             },
         }
diff --git a/openedx/core/djangoapps/content_libraries/api/blocks.py b/openedx/core/djangoapps/content_libraries/api/blocks.py
index 3f6867e72daa..42974f6ff7aa 100644
--- a/openedx/core/djangoapps/content_libraries/api/blocks.py
+++ b/openedx/core/djangoapps/content_libraries/api/blocks.py
@@ -58,7 +58,7 @@
 from .containers import (
     create_container,
     get_container,
-    get_containers_contains_component,
+    get_containers_contains_item,
     update_container_children,
     ContainerMetadata,
     ContainerType,
@@ -229,7 +229,7 @@ def set_library_block_olx(usage_key: LibraryUsageLocatorV2, new_olx_str: str) ->
 
     # For each container, trigger LIBRARY_CONTAINER_UPDATED signal and set background=True to trigger
     # container indexing asynchronously.
-    affected_containers = get_containers_contains_component(usage_key)
+    affected_containers = get_containers_contains_item(usage_key)
     for container in affected_containers:
         LIBRARY_CONTAINER_UPDATED.send_event(
             library_container=LibraryContainerData(
@@ -585,7 +585,7 @@ def delete_library_block(
     component = get_component_from_usage_key(usage_key)
     library_key = usage_key.context_key
     affected_collections = authoring_api.get_entity_collections(component.learning_package_id, component.key)
-    affected_containers = get_containers_contains_component(usage_key)
+    affected_containers = get_containers_contains_item(usage_key)
 
     authoring_api.soft_delete_draft(component.pk, deleted_by=user_id)
 
@@ -673,7 +673,7 @@ def restore_library_block(usage_key: LibraryUsageLocatorV2, user_id: int | None
     # container indexing asynchronously.
     #
     # To update the components count in containers
-    affected_containers = get_containers_contains_component(usage_key)
+    affected_containers = get_containers_contains_item(usage_key)
     for container in affected_containers:
         LIBRARY_CONTAINER_UPDATED.send_event(
             library_container=LibraryContainerData(
diff --git a/openedx/core/djangoapps/content_libraries/api/containers.py b/openedx/core/djangoapps/content_libraries/api/containers.py
index 8e2e486377da..4ec1922fb975 100644
--- a/openedx/core/djangoapps/content_libraries/api/containers.py
+++ b/openedx/core/djangoapps/content_libraries/api/containers.py
@@ -24,7 +24,7 @@
     LIBRARY_CONTAINER_UPDATED,
 )
 from openedx_learning.api import authoring as authoring_api
-from openedx_learning.api.authoring_models import Container, ContainerVersion
+from openedx_learning.api.authoring_models import Container, ContainerVersion, Component
 from openedx.core.djangoapps.content_libraries.api.collections import library_collection_locator
 
 from openedx.core.djangoapps.xblock.api import get_component_from_usage_key
@@ -50,7 +50,7 @@
     "delete_container",
     "restore_container",
     "update_container_children",
-    "get_containers_contains_component",
+    "get_containers_contains_item",
     "publish_container_changes",
 ]
 
@@ -513,7 +513,13 @@ def update_container_children(
                 entities_action=entities_action,
             )
 
-            # TODO add CONTENT_OBJECT_ASSOCIATIONS_CHANGED for subsections
+            for key in children_ids:
+                CONTENT_OBJECT_ASSOCIATIONS_CHANGED.send_event(
+                    content_object=ContentObjectChangedData(
+                        object_id=str(key),
+                        changes=["subsections"],
+                    ),
+                )
         case ContainerType.Section:
             subsections = [_get_container_from_key(key).subsection for key in children_ids]  # type: ignore[arg-type]
             new_version = authoring_api.create_next_section_version(
@@ -524,7 +530,13 @@ def update_container_children(
                 entities_action=entities_action,
             )
 
-            # TODO add CONTENT_OBJECT_ASSOCIATIONS_CHANGED for sections
+            for key in children_ids:
+                CONTENT_OBJECT_ASSOCIATIONS_CHANGED.send_event(
+                    content_object=ContentObjectChangedData(
+                        object_id=str(key),
+                        changes=["sections"],
+                    ),
+                )
         case _:
             raise ValueError(f"Invalid container type: {container_type}")
 
@@ -537,19 +549,26 @@ def update_container_children(
     return ContainerMetadata.from_container(library_key, new_version.container)
 
 
-def get_containers_contains_component(
-    usage_key: LibraryUsageLocatorV2
+def get_containers_contains_item(
+    key: LibraryUsageLocatorV2 | LibraryContainerLocator
 ) -> list[ContainerMetadata]:
     """
-    Get containers that contains the component.
+    Get containers that contains the item,
+    that can be a component or another container.
     """
-    assert isinstance(usage_key, LibraryUsageLocatorV2)
-    component = get_component_from_usage_key(usage_key)
+    item: Component | Container
+
+    if isinstance(key, LibraryUsageLocatorV2):
+        item = get_component_from_usage_key(key)
+
+    elif isinstance(key, LibraryContainerLocator):
+        item = _get_container_from_key(key)
+
     containers = authoring_api.get_containers_with_entity(
-        component.publishable_entity.pk,
+        item.publishable_entity.pk,
     )
     return [
-        ContainerMetadata.from_container(usage_key.context_key, container)
+        ContainerMetadata.from_container(key.lib_key, container)
         for container in containers
     ]
 
diff --git a/openedx/core/djangoapps/content_libraries/library_context.py b/openedx/core/djangoapps/content_libraries/library_context.py
index 34a5a90269fe..4ab66706088d 100644
--- a/openedx/core/djangoapps/content_libraries/library_context.py
+++ b/openedx/core/djangoapps/content_libraries/library_context.py
@@ -121,7 +121,7 @@ def send_container_updated_events(self, usage_key: UsageKeyV2):
         with the given usage_key.
         """
         assert isinstance(usage_key, LibraryUsageLocatorV2)
-        affected_containers = api.get_containers_contains_component(usage_key)
+        affected_containers = api.get_containers_contains_item(usage_key)
         for container in affected_containers:
             LIBRARY_CONTAINER_UPDATED.send_event(
                 library_container=LibraryContainerData(
diff --git a/openedx/core/djangoapps/content_libraries/tasks.py b/openedx/core/djangoapps/content_libraries/tasks.py
index b472126e8ce7..72d2d1b0884f 100644
--- a/openedx/core/djangoapps/content_libraries/tasks.py
+++ b/openedx/core/djangoapps/content_libraries/tasks.py
@@ -99,7 +99,7 @@ def send_events_after_publish(publish_log_pk: int, library_key_str: str) -> None
             # Publishing a container will auto-publish its children, but publishing a single component or all changes
             # in the library will NOT usually include any parent containers. But we do need to notify listeners that the
             # parent container(s) have changed, e.g. so the search index can update the "has_unpublished_changes"
-            for parent_container in api.get_containers_contains_component(usage_key):
+            for parent_container in api.get_containers_contains_item(usage_key):
                 affected_containers.add(parent_container.container_key)
                 # TODO: should this be a CONTAINER_CHILD_PUBLISHED event instead of CONTAINER_PUBLISHED ?
         elif hasattr(record.entity, "container"):
@@ -181,7 +181,7 @@ def send_events_after_revert(draft_change_log_id: int, library_key_str: str) ->
             # If any containers contain this component, their child list / component count may need to be updated
             # e.g. if this was a newly created component in the container and is now deleted, or this was deleted and
             # is now restored.
-            for parent_container in api.get_containers_contains_component(usage_key):
+            for parent_container in api.get_containers_contains_item(usage_key):
                 updated_container_keys.add(parent_container.container_key)
 
             # TODO: do we also need to send CONTENT_OBJECT_ASSOCIATIONS_CHANGED for this component, or is
diff --git a/openedx/core/djangoapps/content_libraries/tests/test_api.py b/openedx/core/djangoapps/content_libraries/tests/test_api.py
index 9517e5d0d2f6..0715848c6424 100644
--- a/openedx/core/djangoapps/content_libraries/tests/test_api.py
+++ b/openedx/core/djangoapps/content_libraries/tests/test_api.py
@@ -746,6 +746,39 @@ def setUp(self) -> None:
         # Create Units
         self.unit1 = api.create_container(self.lib1.library_key, api.ContainerType.Unit, 'unit-1', 'Unit 1', None)
         self.unit2 = api.create_container(self.lib1.library_key, api.ContainerType.Unit, 'unit-2', 'Unit 2', None)
+        self.unit3 = api.create_container(self.lib1.library_key, api.ContainerType.Unit, 'unit-3', 'Unit 3', None)
+
+        # Create Subsections
+        self.subsection1 = api.create_container(
+            self.lib1.library_key,
+            api.ContainerType.Subsection,
+            'subsection-1',
+            'Subsection 1',
+            None,
+        )
+        self.subsection2 = api.create_container(
+            self.lib1.library_key,
+            api.ContainerType.Subsection,
+            'subsection-2',
+            'Subsection 2',
+            None,
+        )
+
+        # Create Sections
+        self.section1 = api.create_container(
+            self.lib1.library_key,
+            api.ContainerType.Section,
+            'section-1',
+            'Section 1',
+            None,
+        )
+        self.section2 = api.create_container(
+            self.lib1.library_key,
+            api.ContainerType.Section,
+            'section-2',
+            'Section 2',
+            None,
+        )
 
         # Create XBlocks
         # Create some library blocks in lib1
@@ -753,6 +786,9 @@ def setUp(self) -> None:
             self.lib1.library_key, "problem", "problem1",
         )
         self.problem_block_usage_key = LibraryUsageLocatorV2.from_string(self.problem_block["id"])
+        self.problem_block_2 = self._add_block_to_library(
+            self.lib1.library_key, "problem", "problem2",
+        )
         self.html_block = self._add_block_to_library(
             self.lib1.library_key, "html", "html1",
         )
@@ -770,9 +806,37 @@ def setUp(self) -> None:
             None,
         )
 
-    def test_get_containers_contains_component(self) -> None:
-        problem_block_containers = api.get_containers_contains_component(self.problem_block_usage_key)
-        html_block_containers = api.get_containers_contains_component(self.html_block_usage_key)
+        # Add units to subsections
+        api.update_container_children(
+            self.subsection1.container_key,
+            [self.unit1.container_key, self.unit2.container_key],
+            None,
+        )
+        api.update_container_children(
+            self.subsection2.container_key,
+            [self.unit1.container_key],
+            None,
+        )
+
+        # Add subsections to sections
+        api.update_container_children(
+            self.section1.container_key,
+            [self.subsection1.container_key, self.subsection2.container_key],
+            None,
+        )
+        api.update_container_children(
+            self.section2.container_key,
+            [self.subsection1.container_key],
+            None,
+        )
+
+    def test_get_containers_contains_item(self):
+        problem_block_containers = api.get_containers_contains_item(self.problem_block_usage_key)
+        html_block_containers = api.get_containers_contains_item(self.html_block_usage_key)
+        unit_1_containers = api.get_containers_contains_item(self.unit1.container_key)
+        unit_2_containers = api.get_containers_contains_item(self.unit2.container_key)
+        subsection_1_containers = api.get_containers_contains_item(self.subsection1.container_key)
+        subsection_2_containers = api.get_containers_contains_item(self.subsection2.container_key)
 
         assert len(problem_block_containers) == 1
         assert problem_block_containers[0].container_key == self.unit1.container_key
@@ -781,7 +845,21 @@ def test_get_containers_contains_component(self) -> None:
         assert html_block_containers[0].container_key == self.unit1.container_key
         assert html_block_containers[1].container_key == self.unit2.container_key
 
-    def _validate_calls_of_html_block(self, event_mock) -> None:
+        assert len(unit_1_containers) == 2
+        assert unit_1_containers[0].container_key == self.subsection1.container_key
+        assert unit_1_containers[1].container_key == self.subsection2.container_key
+
+        assert len(unit_2_containers) == 1
+        assert unit_2_containers[0].container_key == self.subsection1.container_key
+
+        assert len(subsection_1_containers) == 2
+        assert subsection_1_containers[0].container_key == self.section1.container_key
+        assert subsection_1_containers[1].container_key == self.section2.container_key
+
+        assert len(subsection_2_containers) == 1
+        assert subsection_2_containers[0].container_key == self.section1.container_key
+
+    def _validate_calls_of_html_block(self, event_mock):
         """
         Validate that the `event_mock` has been called twice
         using the `LIBRARY_CONTAINER_UPDATED` signal.
@@ -875,6 +953,76 @@ def test_call_object_changed_signal_when_remove_component(self) -> None:
             event_reciver.call_args_list[0].kwargs,
         )
 
+    def test_call_object_changed_signal_when_remove_unit(self) -> None:
+        unit4 = api.create_container(self.lib1.library_key, api.ContainerType.Unit, 'unit-4', 'Unit 4', None)
+
+        api.update_container_children(
+            self.subsection2.container_key,
+            [unit4.container_key],
+            None,
+            entities_action=authoring_api.ChildrenEntitiesAction.APPEND,
+        )
+
+        event_reciver = mock.Mock()
+        CONTENT_OBJECT_ASSOCIATIONS_CHANGED.connect(event_reciver)
+        api.update_container_children(
+            self.subsection2.container_key,
+            [unit4.container_key],
+            None,
+            entities_action=authoring_api.ChildrenEntitiesAction.REMOVE,
+        )
+
+        assert event_reciver.call_count == 1
+        self.assertDictContainsSubset(
+            {
+                "signal": CONTENT_OBJECT_ASSOCIATIONS_CHANGED,
+                "sender": None,
+                "content_object": ContentObjectChangedData(
+                    object_id=str(unit4.container_key),
+                    changes=["subsections"],
+                ),
+            },
+            event_reciver.call_args_list[0].kwargs,
+        )
+
+    def test_call_object_changed_signal_when_remove_subsection(self) -> None:
+        subsection3 = api.create_container(
+            self.lib1.library_key,
+            api.ContainerType.Subsection,
+            'subsection-3',
+            'Subsection 3',
+            None,
+        )
+
+        api.update_container_children(
+            self.section2.container_key,
+            [subsection3.container_key],
+            None,
+            entities_action=authoring_api.ChildrenEntitiesAction.APPEND,
+        )
+
+        event_reciver = mock.Mock()
+        CONTENT_OBJECT_ASSOCIATIONS_CHANGED.connect(event_reciver)
+        api.update_container_children(
+            self.section2.container_key,
+            [subsection3.container_key],
+            None,
+            entities_action=authoring_api.ChildrenEntitiesAction.REMOVE,
+        )
+
+        assert event_reciver.call_count == 1
+        self.assertDictContainsSubset(
+            {
+                "signal": CONTENT_OBJECT_ASSOCIATIONS_CHANGED,
+                "sender": None,
+                "content_object": ContentObjectChangedData(
+                    object_id=str(subsection3.container_key),
+                    changes=["sections"],
+                ),
+            },
+            event_reciver.call_args_list[0].kwargs,
+        )
+
     def test_call_object_changed_signal_when_add_component(self) -> None:
         event_reciver = mock.Mock()
         CONTENT_OBJECT_ASSOCIATIONS_CHANGED.connect(event_reciver)
@@ -919,19 +1067,104 @@ def test_call_object_changed_signal_when_add_component(self) -> None:
             event_reciver.call_args_list[1].kwargs,
         )
 
+    def test_call_object_changed_signal_when_add_unit(self) -> None:
+        event_reciver = mock.Mock()
+        CONTENT_OBJECT_ASSOCIATIONS_CHANGED.connect(event_reciver)
+
+        unit4 = api.create_container(self.lib1.library_key, api.ContainerType.Unit, 'unit-4', 'Unit 4', None)
+        unit5 = api.create_container(self.lib1.library_key, api.ContainerType.Unit, 'unit-5', 'Unit 5', None)
+
+        api.update_container_children(
+            self.subsection2.container_key,
+            [unit4.container_key, unit5.container_key],
+            None,
+            entities_action=authoring_api.ChildrenEntitiesAction.APPEND,
+        )
+        assert event_reciver.call_count == 2
+        self.assertDictContainsSubset(
+            {
+                "signal": CONTENT_OBJECT_ASSOCIATIONS_CHANGED,
+                "sender": None,
+                "content_object": ContentObjectChangedData(
+                    object_id=str(unit4.container_key),
+                    changes=["subsections"],
+                ),
+            },
+            event_reciver.call_args_list[0].kwargs,
+        )
+        self.assertDictContainsSubset(
+            {
+                "signal": CONTENT_OBJECT_ASSOCIATIONS_CHANGED,
+                "sender": None,
+                "content_object": ContentObjectChangedData(
+                    object_id=str(unit5.container_key),
+                    changes=["subsections"],
+                ),
+            },
+            event_reciver.call_args_list[1].kwargs,
+        )
+
+    def test_call_object_changed_signal_when_add_subsection(self) -> None:
+        event_reciver = mock.Mock()
+        CONTENT_OBJECT_ASSOCIATIONS_CHANGED.connect(event_reciver)
+
+        subsection3 = api.create_container(
+            self.lib1.library_key,
+            api.ContainerType.Subsection,
+            'subsection-3',
+            'Subsection 3',
+            None,
+        )
+        subsection4 = api.create_container(
+            self.lib1.library_key,
+            api.ContainerType.Subsection,
+            'subsection-4',
+            'Subsection 4',
+            None,
+        )
+        api.update_container_children(
+            self.section2.container_key,
+            [subsection3.container_key, subsection4.container_key],
+            None,
+            entities_action=authoring_api.ChildrenEntitiesAction.APPEND,
+        )
+        assert event_reciver.call_count == 2
+        self.assertDictContainsSubset(
+            {
+                "signal": CONTENT_OBJECT_ASSOCIATIONS_CHANGED,
+                "sender": None,
+                "content_object": ContentObjectChangedData(
+                    object_id=str(subsection3.container_key),
+                    changes=["sections"],
+                ),
+            },
+            event_reciver.call_args_list[0].kwargs,
+        )
+        self.assertDictContainsSubset(
+            {
+                "signal": CONTENT_OBJECT_ASSOCIATIONS_CHANGED,
+                "sender": None,
+                "content_object": ContentObjectChangedData(
+                    object_id=str(subsection4.container_key),
+                    changes=["sections"],
+                ),
+            },
+            event_reciver.call_args_list[1].kwargs,
+        )
+
     def test_delete_component_and_revert(self) -> None:
         """
         When a component is deleted and then the delete is reverted, signals
         will be emitted to update any containing containers.
         """
         # Add components and publish
-        api.update_container_children(self.unit1.container_key, [
-            LibraryUsageLocatorV2.from_string(self.problem_block["id"]),
+        api.update_container_children(self.unit3.container_key, [
+            LibraryUsageLocatorV2.from_string(self.problem_block_2["id"]),
         ], user_id=None)
         api.publish_changes(self.lib1.library_key)
 
         # Delete component and revert
-        api.delete_library_block(LibraryUsageLocatorV2.from_string(self.problem_block["id"]))
+        api.delete_library_block(LibraryUsageLocatorV2.from_string(self.problem_block_2["id"]))
 
         container_event_receiver = mock.Mock()
         LIBRARY_CONTAINER_UPDATED.connect(container_event_receiver)
@@ -942,5 +1175,5 @@ def test_delete_component_and_revert(self) -> None:
         assert {
             "signal": LIBRARY_CONTAINER_UPDATED,
             "sender": None,
-            "library_container": LibraryContainerData(container_key=self.unit1.container_key),
+            "library_container": LibraryContainerData(container_key=self.unit3.container_key),
         }.items() <= container_event_receiver.call_args_list[0].kwargs.items()