diff --git a/redbot/cogs/downloader/repo_manager.py b/redbot/cogs/downloader/repo_manager.py
index 8d9b3fa06cc..ef07d69b992 100644
--- a/redbot/cogs/downloader/repo_manager.py
+++ b/redbot/cogs/downloader/repo_manager.py
@@ -1044,7 +1044,7 @@ def repos_folder(self) -> Path:
         return data_folder / "repos"
 
     def does_repo_exist(self, name: str) -> bool:
-        return name in self._repos
+        return name.lower() in self._repos
 
     @staticmethod
     def validate_and_normalize_repo_name(name: str) -> str:
@@ -1070,6 +1070,7 @@ async def add_repo(self, url: str, name: str, branch: Optional[str] = None) -> R
             New Repo object representing the cloned repository.
 
         """
+        name = name.lower()  # convert the repo name to lower case
         if self.does_repo_exist(name):
             raise errors.ExistingGitRepo(
                 "That repo name you provided already exists. Please choose another."
@@ -1102,6 +1103,7 @@ def get_repo(self, name: str) -> Optional[Repo]:
             Repo object for the repository, if it exists.
 
         """
+        name = name.lower()
         return self._repos.get(name, None)
 
     @property
@@ -1146,6 +1148,7 @@ async def delete_repo(self, name: str) -> None:
             If the repo does not exist.
 
         """
+        name = name.lower()
         repo = self.get_repo(name)
         if repo is None:
             raise errors.MissingGitRepo(f"There is no repo with the name {name}")
@@ -1172,6 +1175,7 @@ async def update_repo(self, repo_name: str) -> Tuple[Repo, Tuple[str, str]]:
             A 2-`tuple` with Repo object and a 2-`tuple` of `str`
             containing old and new commit hashes.
         """
+        repo_name = repo_name.lower()
         repo = self._repos[repo_name]
         old, new = await repo.update()
         return (repo, (old, new))
diff --git a/tests/cogs/downloader/test_repo_manager_unittest.py b/tests/cogs/downloader/test_repo_manager_unittest.py
new file mode 100644
index 00000000000..7afb4899b0b
--- /dev/null
+++ b/tests/cogs/downloader/test_repo_manager_unittest.py
@@ -0,0 +1,84 @@
+import pytest
+import asyncio
+from pathlib import Path
+from unittest.mock import AsyncMock, patch
+
+from redbot.cogs.downloader.repo_manager import RepoManager, errors, Repo
+
+
+@pytest.mark.asyncio
+async def test_add_repo_case_insensitive(tmp_path):
+    manager = RepoManager()
+    await manager.initialize()
+
+    # Mock Repo.clone so it doesn't actually clone anything
+    with patch("redbot.cogs.downloader.repo_manager.Repo.clone", new_callable=AsyncMock):
+        # Add repo with uppercase name
+        repo1 = await manager.add_repo("https://example.com/repo.git", "TestRepo")
+
+        # Adding same repo with lowercase name should raise ExistingGitRepo
+        with pytest.raises(errors.ExistingGitRepo):
+            await manager.add_repo("https://example.com/repo.git", "testrepo")
+
+        # Check that repo is stored with lowercase key
+        assert "testrepo" in manager._repos
+        assert manager._repos["testrepo"] == repo1
+
+
+@pytest.mark.asyncio
+async def test_delete_repo_case_insensitive(tmp_path):
+    manager = RepoManager()
+    await manager.initialize()
+
+    with patch("redbot.cogs.downloader.repo_manager.Repo.clone", new_callable=AsyncMock):
+        await manager.add_repo("https://example.com/repo.git", "MyRepo")
+
+    # Deleting with different casing should succeed
+    await manager.delete_repo("myrepo")  # lowercase
+    assert "myrepo" not in manager._repos
+
+    # Deleting a non-existent repo should raise MissingGitRepo
+    with pytest.raises(errors.MissingGitRepo):
+        await manager.delete_repo("myrepo")
+
+
+@pytest.mark.asyncio
+async def test_update_repo_case_insensitive(tmp_path):
+    manager = RepoManager()
+    await manager.initialize()
+
+    # Mock Repo.update to return fake commit hashes
+    fake_update = AsyncMock(return_value=("oldhash", "newhash"))
+    with patch("redbot.cogs.downloader.repo_manager.Repo.clone", new_callable=AsyncMock):
+        repo = await manager.add_repo("https://example.com/repo.git", "UpdateRepo")
+    repo.update = fake_update
+
+    # Call update_repo with different casing
+    updated_repo, (old, new) = await manager.update_repo("updaterepo")
+    assert updated_repo == repo
+    assert old == "oldhash"
+    assert new == "newhash"
+
+
+@pytest.mark.asyncio
+async def test_repo_existing_git_repo(tmp_path):
+    # Create a Repo instance
+    repo = Repo(
+        name="TestRepo",
+        url="https://example.com/repo.git",
+        branch=None,
+        commit="",
+        folder_path=tmp_path,
+    )
+
+    # Case 1: .git folder does not exist
+    exists, path = repo._existing_git_repo()
+    assert exists is False
+    assert path == tmp_path / ".git"
+
+    # Case 2: .git folder exists
+    git_dir = tmp_path / ".git"
+    git_dir.mkdir()
+    exists, path = repo._existing_git_repo()
+    assert exists is True
+    assert path == git_dir