diff --git a/litellm/proxy/management_endpoints/access_group_endpoints.py b/litellm/proxy/management_endpoints/access_group_endpoints.py
index e73ec5eafc..100b1d2659 100644
--- a/litellm/proxy/management_endpoints/access_group_endpoints.py
+++ b/litellm/proxy/management_endpoints/access_group_endpoints.py
@@ -153,10 +153,19 @@ async def update_access_group(
     for field, value in data.model_dump(exclude_unset=True).items():
         update_data[field] = value
 
-    record = await prisma_client.db.litellm_accessgrouptable.update(
-        where={"access_group_id": access_group_id},
-        data=update_data,
-    )
+    try:
+        record = await prisma_client.db.litellm_accessgrouptable.update(
+            where={"access_group_id": access_group_id},
+            data=update_data,
+        )
+    except Exception as e:
+        # Unique constraint violation (e.g. access_group_name already exists).
+        if "unique constraint" in str(e).lower() or "P2002" in str(e):
+            raise HTTPException(
+                status_code=status.HTTP_409_CONFLICT,
+                detail=f"Access group '{update_data.get('access_group_name', '')}' already exists",
+            )
+        raise
     return _record_to_response(record)
 
 
diff --git a/litellm/types/access_group.py b/litellm/types/access_group.py
index 09ffd60996..e26ebe0062 100644
--- a/litellm/types/access_group.py
+++ b/litellm/types/access_group.py
@@ -15,6 +15,7 @@ class AccessGroupCreateRequest(BaseModel):
 
 
 class AccessGroupUpdateRequest(BaseModel):
+    access_group_name: Optional[str] = None
     description: Optional[str] = None
     access_model_names: Optional[List[str]] = None
     access_mcp_server_ids: Optional[List[str]] = None
diff --git a/tests/test_litellm/proxy/management_endpoints/test_access_group_endpoints.py b/tests/test_litellm/proxy/management_endpoints/test_access_group_endpoints.py
index ee64c534b4..54df8941fa 100644
--- a/tests/test_litellm/proxy/management_endpoints/test_access_group_endpoints.py
+++ b/tests/test_litellm/proxy/management_endpoints/test_access_group_endpoints.py
@@ -431,6 +431,57 @@ def test_update_access_group_empty_body(client_and_mocks):
     assert call_kwargs["data"]["updated_by"] == "admin_user"
 
 
+def test_update_access_group_name_success(client_and_mocks):
+    """Update access_group_name succeeds when new name is unique."""
+    client, _, mock_table = client_and_mocks
+
+    existing = _make_access_group_record(access_group_id="ag-update", access_group_name="old-name")
+    mock_table.find_unique = AsyncMock(return_value=existing)
+
+    resp = client.put("/v1/access_group/ag-update", json={"access_group_name": "new-name"})
+    assert resp.status_code == 200
+    mock_table.update.assert_awaited_once()
+    call_kwargs = mock_table.update.call_args.kwargs
+    assert call_kwargs["data"]["access_group_name"] == "new-name"
+
+
+def test_update_access_group_name_duplicate_conflict(client_and_mocks):
+    """Update access_group_name to existing name returns 409 (unique constraint)."""
+    client, _, mock_table = client_and_mocks
+
+    existing = _make_access_group_record(access_group_id="ag-update", access_group_name="old-name")
+    mock_table.find_unique = AsyncMock(return_value=existing)
+    mock_table.update = AsyncMock(
+        side_effect=Exception("Unique constraint failed on the fields: (`access_group_name`)")
+    )
+
+    resp = client.put("/v1/access_group/ag-update", json={"access_group_name": "taken-name"})
+    assert resp.status_code == 409
+    assert "already exists" in resp.json()["detail"]
+    mock_table.update.assert_awaited_once()
+
+
+@pytest.mark.parametrize(
+    "error_message",
+    [
+        "Unique constraint failed on the fields: (`access_group_name`)",
+        "P2002: Unique constraint failed",
+        "unique constraint violation",
+    ],
+)
+def test_update_access_group_name_unique_constraint_returns_409(client_and_mocks, error_message):
+    """Update access_group_name: Prisma unique constraint surfaces as 409."""
+    client, _, mock_table = client_and_mocks
+
+    existing = _make_access_group_record(access_group_id="ag-update", access_group_name="old-name")
+    mock_table.find_unique = AsyncMock(return_value=existing)
+    mock_table.update = AsyncMock(side_effect=Exception(error_message))
+
+    resp = client.put("/v1/access_group/ag-update", json={"access_group_name": "race-name"})
+    assert resp.status_code == 409
+    assert "already exists" in resp.json()["detail"]
+
+
 # ---------------------------------------------------------------------------
 # DELETE
 # ---------------------------------------------------------------------------