diff --git a/.changeset/true-pens-give.md b/.changeset/true-pens-give.md
new file mode 100644
index 0000000..83fe511
--- /dev/null
+++ b/.changeset/true-pens-give.md
@@ -0,0 +1,5 @@
+---
+"@itwin/scenes-client": patch
+---
+
+Add `lastModifiedById` to `Scene`, `SceneObject`, and `Tag` response interfaces. Tracks the id of the user who last made changes.
diff --git a/packages/scenes-client/README.md b/packages/scenes-client/README.md
index 8bb94fd..08abb13 100644
--- a/packages/scenes-client/README.md
+++ b/packages/scenes-client/README.md
@@ -44,6 +44,7 @@ console.log(sceneResponse.scene);
   displayName: "My Scene",
   iTwinId: "<itwin_id>",
   createdById: "<creator_id>",
+  lastModifiedById: "<editor_id>",
   creationTime: "2025-01-01T10:00:00.000Z",
   lastModified: "2025-01-01T10:01:00.000Z",
   sceneData: { objects: [...] },
@@ -176,6 +177,7 @@ console.log(objectResponse.object);
   version: "1.0.0",
   data: { ... },
   createdById: "<creator_id>",
+  lastModifiedById: "<editor_id>",
   creationTime: "2025-01-01T10:00:00.000Z",
   lastModified: "2025-01-01T10:01:00.000Z"
 }
@@ -470,6 +472,7 @@ console.log(tagResponse.tag);
   displayName: "Structural",
   iTwinId: "<itwin_id>",
   createdById: "<creator_id>",
+  lastModifiedById: "<editor_id>",
   creationTime: "2025-01-01T10:00:00.000Z",
   lastModified: "2025-01-01T10:01:00.000Z"
 }
diff --git a/packages/scenes-client/src/models/object/sceneObject.ts b/packages/scenes-client/src/models/object/sceneObject.ts
index 7134db6..17bd32e 100644
--- a/packages/scenes-client/src/models/object/sceneObject.ts
+++ b/packages/scenes-client/src/models/object/sceneObject.ts
@@ -21,6 +21,8 @@ interface SceneObjectResponseMetadata {
   sceneId: string;
   /** Id of the user who created the scene object (UUID). */
   createdById: string;
+  /** Id of the user who last modified the scene object (UUID). */
+  lastModifiedById: string;
   /** Time the scene object was created as an ISO8601 string, 'YYYY-MM-DDTHH:mm:ss.sssZ'. */
   creationTime: string;
   /** Time the scene object was last modified as an ISO8601 string, 'YYYY-MM-DDTHH:mm:ss.sssZ'. */
@@ -65,6 +67,7 @@ export function isSceneObject(v: unknown): v is SceneObject {
     typeof v.id === "string" &&
     typeof v.sceneId === "string" &&
     typeof v.createdById === "string" &&
+    typeof v.lastModifiedById === "string" &&
     typeof v.creationTime === "string" &&
     typeof v.lastModified === "string" &&
     isSceneObjectCreate(v)
diff --git a/packages/scenes-client/src/models/object/sceneObjectMinimal.ts b/packages/scenes-client/src/models/object/sceneObjectMinimal.ts
index 4f063b6..5a4c175 100644
--- a/packages/scenes-client/src/models/object/sceneObjectMinimal.ts
+++ b/packages/scenes-client/src/models/object/sceneObjectMinimal.ts
@@ -8,7 +8,7 @@ import { isSceneObjectCreate } from "./sceneObjectCreate.js";
 
 export type SceneObjectMinimal = UnionOmit<
   SceneObject,
-  "sceneId" | "createdById" | "creationTime" | "lastModified"
+  "sceneId" | "createdById" | "lastModifiedById" | "creationTime" | "lastModified"
 >;
 
 export function isSceneObjectMinimal(v: unknown): v is SceneObjectMinimal {
diff --git a/packages/scenes-client/src/models/scene/sceneMinimal.ts b/packages/scenes-client/src/models/scene/sceneMinimal.ts
index 9a7e909..c337771 100644
--- a/packages/scenes-client/src/models/scene/sceneMinimal.ts
+++ b/packages/scenes-client/src/models/scene/sceneMinimal.ts
@@ -16,6 +16,8 @@ export interface SceneMinimal {
   description?: string;
   /** Id of the user who created the scene (UUID). */
   createdById: string;
+  /** Id of the user who last modified the scene (UUID). */
+  lastModifiedById: string;
   /** iTwin Id associated with the scene (UUID). */
   iTwinId: string;
   /** Time the scene was created as an ISO8601 string, 'YYYY-MM-DDTHH:mm:ss.sssZ'. */
@@ -32,6 +34,7 @@ export function isSceneMinimal(v: unknown): v is SceneMinimal {
     typeof v.id === "string" &&
     typeof v.displayName === "string" &&
     typeof v.createdById === "string" &&
+    typeof v.lastModifiedById === "string" &&
     typeof v.iTwinId === "string" &&
     typeof v.creationTime === "string" &&
     typeof v.lastModified === "string" &&
diff --git a/packages/scenes-client/src/models/tag/tag.ts b/packages/scenes-client/src/models/tag/tag.ts
index 7cdeb49..47fac22 100644
--- a/packages/scenes-client/src/models/tag/tag.ts
+++ b/packages/scenes-client/src/models/tag/tag.ts
@@ -11,6 +11,8 @@ export interface Tag extends TagMinimal {
   iTwinId: string;
   /** Id of the user who created the tag (UUID). */
   createdById: string;
+  /** Id of the user who last modified the tag (UUID). */
+  lastModifiedById: string;
   /** Time the tag was created as an ISO8601 string, 'YYYY-MM-DDTHH:mm:ss.sssZ'. */
   creationTime: string;
   /** Time the tag was last modified as an ISO8601 string, 'YYYY-MM-DDTHH:mm:ss.sssZ'. */
@@ -23,6 +25,7 @@ export function isTag(v: unknown): v is Tag {
     isTagMinimal(v) &&
     typeof v.iTwinId === "string" &&
     typeof v.createdById === "string" &&
+    typeof v.lastModifiedById === "string" &&
     typeof v.creationTime === "string" &&
     typeof v.lastModified === "string"
   );
diff --git a/packages/scenes-client/tests/unit.test.ts b/packages/scenes-client/tests/unit.test.ts
index 54b0cb1..ba7b547 100644
--- a/packages/scenes-client/tests/unit.test.ts
+++ b/packages/scenes-client/tests/unit.test.ts
@@ -765,6 +765,7 @@ const exampleSceneResponse: SceneResponse = {
     description: "Some Description XYZ123",
     iTwinId: "itwin-1",
     createdById: "user-1",
+    lastModifiedById: "user-1",
     creationTime: "2025-07-16T15:00:00.000Z",
     lastModified: "2025-07-16T15:00:00.000Z",
     tags: [{ id: "tag-1", displayName: "Tag 1" }],
@@ -788,6 +789,7 @@ const exampleSceneMetadataResponse: SceneMetadataResponse = {
     description: "Some Description XYZ123",
     iTwinId: "itwin-1",
     createdById: "user-1",
+    lastModifiedById: "user-1",
     creationTime: "2025-07-16T15:00:00.000Z",
     lastModified: "2025-07-16T15:00:00.000Z",
     tags: [{ id: "tag-1", displayName: "Tag 1" }],
@@ -807,6 +809,7 @@ const exampleSceneListResponse: SceneListResponse = {
       description: "Some Description XYZ123",
       iTwinId: "itwin-1",
       createdById: "user-1",
+      lastModifiedById: "user-1",
       creationTime: "2025-07-16T15:00:00.000Z",
       lastModified: "2025-07-16T15:00:00.000Z",
       tags: [{ id: "tag-1", displayName: "Tag 1" }],
@@ -821,6 +824,7 @@ const exampleTagResponse: TagResponse = {
     displayName: "Tag 1",
     iTwinId: "itwin-1",
     createdById: "user-1",
+    lastModifiedById: "user-1",
     creationTime: "2025-07-16T15:00:00.000Z",
     lastModified: "2025-07-16T15:00:00.000Z",
   },
@@ -840,6 +844,7 @@ const exampleSceneObjectResponse: SceneObjectResponse = {
     data: {},
     sceneId: "scene-1",
     createdById: "user-1",
+    lastModifiedById: "user-1",
     creationTime: "2025-07-16T15:00:00.000Z",
     lastModified: "2025-07-16T15:00:00.000Z",
   },