diff --git a/litellm/proxy/health_endpoints/_health_endpoints.py b/litellm/proxy/health_endpoints/_health_endpoints.py
index c20991b8d43..c5c892eb720 100644
--- a/litellm/proxy/health_endpoints/_health_endpoints.py
+++ b/litellm/proxy/health_endpoints/_health_endpoints.py
@@ -28,6 +28,7 @@ from litellm.proxy._types import (
     UserAPIKeyAuth,
     WebhookEvent,
 )
+from litellm.proxy.auth.model_checks import get_key_models
 from litellm.proxy.auth.user_api_key_auth import user_api_key_auth
 from litellm.proxy.db.exception_handler import PrismaDBExceptionHandler
 from litellm.proxy.health_check import (
@@ -994,17 +995,20 @@ async def health_endpoint(
         # response but NOT in the background-cache /health response. This is
         # surfaced via the "warnings" field below so operators can fix the
         # missing model_info.id rather than guess at the discrepancy.
-        # Keys granted SpecialModelNames.all_proxy_models carry the literal
-        # "all-proxy-models" entry, which matches no real model_name; treat
-        # them as unrestricted instead of filtering the list down to nothing.
-        # Keys granted SpecialModelNames.all_team_models inherit the parent
-        # team's allowlist (same semantics as get_key_models in
-        # model_checks.py). Without a team_id the sentinel cannot resolve and
-        # stays in the list, matching nothing; denied rather than
-        # unrestricted, mirroring _resolve_key_models_for_auth_check.
-        accessible_models = list(user_api_key_dict.models)
-        if SpecialModelNames.all_team_models.value in accessible_models and user_api_key_dict.team_id is not None:
-            accessible_models = list(user_api_key_dict.team_models)
+        # Resolve the caller's effective allowlist via get_key_models so the
+        # access sentinels (all-proxy-models / all-team-models) and access
+        # groups expand to concrete model_names. Filtering on raw .models would
+        # drop every deployment for keys whose entry is a group or sentinel
+        # (issue #28206).
+        accessible_models = get_key_models(
+            user_api_key_dict=user_api_key_dict,
+            proxy_model_list=(
+                llm_router.get_model_names() if llm_router is not None else []
+            ),
+            model_access_groups=(
+                llm_router.get_model_access_groups() if llm_router is not None else {}
+            ),
+        )
         restrict_to_allowed_models = (
             len(accessible_models) > 0 and SpecialModelNames.all_proxy_models.value not in accessible_models
         )
diff --git a/tests/test_litellm/proxy/health_endpoints/test_health_endpoints.py b/tests/test_litellm/proxy/health_endpoints/test_health_endpoints.py
index a04ad5598df..7577feb49da 100644
--- a/tests/test_litellm/proxy/health_endpoints/test_health_endpoints.py
+++ b/tests/test_litellm/proxy/health_endpoints/test_health_endpoints.py
@@ -1353,6 +1353,74 @@ async def test_health_endpoint_resolves_all_team_models_to_team_allowlist():
     }, f"all-team-models key should health-check the team's models: {returned_names}"
 
 
+@pytest.mark.asyncio
+async def test_health_endpoint_expands_access_group_models():
+    """
+    A key scoped to an access group carries the group name (not a real
+    model_name) in user_api_key_dict.models. health_endpoint() must expand the
+    group to its member model_names before filtering; otherwise the group name
+    matches nothing and the model list zeroes out (issue #28206).
+    """
+    from litellm.proxy._types import UserAPIKeyAuth
+    from litellm.proxy.health_endpoints._health_endpoints import health_endpoint
+
+    full_model_list = [
+        {
+            "model_name": "model-a",
+            "litellm_params": {"model": "openai/gpt-4o"},
+            "model_info": {"id": "id-a"},
+        },
+        {
+            "model_name": "model-b",
+            "litellm_params": {"model": "openai/gpt-4o"},
+            "model_info": {"id": "id-b"},
+        },
+    ]
+
+    mock_router = MagicMock()
+    mock_router.get_model_names.return_value = ["model-a", "model-b"]
+    mock_router.get_model_access_groups.return_value = {"beta-group": ["model-b"]}
+
+    user_api_key_dict = UserAPIKeyAuth(
+        api_key="hashed-test-key",
+        models=["beta-group"],
+    )
+
+    captured: dict = {}
+
+    async def fake_perform(**kwargs):
+        captured["model_list"] = kwargs["model_list"]
+        return {
+            "healthy_endpoints": [],
+            "unhealthy_endpoints": [],
+            "healthy_count": 0,
+            "unhealthy_count": 0,
+        }
+
+    with (
+        patch("litellm.proxy.proxy_server.llm_model_list", full_model_list),
+        patch("litellm.proxy.proxy_server.llm_router", mock_router),
+        patch("litellm.proxy.proxy_server.prisma_client", None),
+        patch("litellm.proxy.proxy_server.use_background_health_checks", False),
+        patch("litellm.proxy.proxy_server.user_model", None),
+        patch("litellm.proxy.proxy_server.health_check_results", {}),
+        patch("litellm.proxy.proxy_server.health_check_details", True),
+        patch("litellm.proxy.proxy_server.health_check_concurrency", 1),
+        patch(
+            "litellm.proxy.health_endpoints._health_endpoints._perform_health_check_and_save",
+            side_effect=fake_perform,
+        ),
+    ):
+        from fastapi import Response
+
+        await health_endpoint(response=Response(), user_api_key_dict=user_api_key_dict)
+
+    returned_names = {m["model_name"] for m in captured["model_list"]}
+    assert returned_names == {
+        "model-b"
+    }, f"access-group key should expand to its member models: {returned_names}"
+
+
 @pytest.mark.asyncio
 async def test_health_endpoint_filters_background_cache_by_user_access():
     """