diff --git a/litellm/llms/vertex_ai/vertex_llm_base.py b/litellm/llms/vertex_ai/vertex_llm_base.py
index 445e34966a9..fd16427fabe 100644
--- a/litellm/llms/vertex_ai/vertex_llm_base.py
+++ b/litellm/llms/vertex_ai/vertex_llm_base.py
@@ -37,6 +37,15 @@ else:
     GoogleCredentialsObject = Any
 
 
+def _import_token_state() -> "type[TokenState]":
+    try:
+        from google.auth.credentials import TokenState
+    except ImportError:
+        raise ImportError(GOOGLE_IMPORT_ERROR_MESSAGE)
+
+    return TokenState
+
+
 class VertexBase:
     def __init__(self) -> None:
         super().__init__()
@@ -397,7 +406,7 @@ class VertexBase:
         Look up cached credentials and return (token, project_id) if the token
         is FRESH. Returns None if not cached or not fresh.
         """
-        from google.auth.credentials import TokenState
+        TokenState: Final = _import_token_state()
 
         creds, cached_project_id = self._unpack_cached_credentials(credential_cache_key)
         if (
@@ -423,7 +432,7 @@ class VertexBase:
         credentials object so the caller can schedule a background refresh
         without holding the per-key async lock.
         """
-        from google.auth.credentials import TokenState
+        TokenState: Final = _import_token_state()
 
         creds, cached_project_id = self._unpack_cached_credentials(credential_cache_key)
         if creds is None:
@@ -457,7 +466,7 @@ class VertexBase:
         Falls back to expired/valid checks if token_state is unavailable
         (e.g. older google-auth versions or mock objects in tests).
         """
-        from google.auth.credentials import TokenState as _TokenState
+        _TokenState: Final = _import_token_state()
 
         token_state: Final = getattr(credentials, "token_state", None)
         if isinstance(token_state, _TokenState):
@@ -978,7 +987,7 @@ class VertexBase:
         only one coroutine refreshes while others wait on the lock. Uses native
         async refresh for service_account and authorized_user credentials.
         """
-        from google.auth.credentials import TokenState
+        TokenState: Final = _import_token_state()
 
         cache_credentials: Final = json.dumps(credentials) if isinstance(credentials, dict) else credentials
         credential_cache_key: Final = (cache_credentials, project_id)
diff --git a/tests/test_litellm/llms/vertex_ai/test_vertex_llm_base.py b/tests/test_litellm/llms/vertex_ai/test_vertex_llm_base.py
index 18fc239b7c6..75d9086ced1 100644
--- a/tests/test_litellm/llms/vertex_ai/test_vertex_llm_base.py
+++ b/tests/test_litellm/llms/vertex_ai/test_vertex_llm_base.py
@@ -2088,3 +2088,33 @@ class TestVertexBase:
 
             assert token == "cached-token"
             assert not mock_get_lock.called, "Fast path should not acquire lock"
+
+    @pytest.mark.asyncio
+    async def test_missing_google_auth_raises_actionable_import_error(self):
+        """Test that a missing google-auth surfaces the install hint, not a raw ModuleNotFoundError"""
+        vertex_base = VertexBase()
+
+        with patch.dict("sys.modules", {"google.auth.credentials": None}):
+            with pytest.raises(ImportError, match="Google Cloud SDK not found"):
+                await vertex_base._ensure_access_token_async(
+                    credentials={"type": "service_account", "project_id": "project-1"},
+                    project_id="project-1",
+                    custom_llm_provider="vertex_ai",
+                )
+
+    @pytest.mark.parametrize(
+        "call_helper",
+        [
+            lambda vb: vb._try_get_cached_token(("key", None), "project-1"),
+            lambda vb: vb._try_get_usable_cached_token(("key", None), "project-1"),
+            lambda vb: vb._get_token_state(MagicMock()),
+        ],
+        ids=["try_get_cached_token", "try_get_usable_cached_token", "get_token_state"],
+    )
+    def test_token_state_helpers_raise_actionable_import_error(self, call_helper):
+        """Test that every TokenState call site surfaces the install hint"""
+        vertex_base = VertexBase()
+
+        with patch.dict("sys.modules", {"google.auth.credentials": None}):
+            with pytest.raises(ImportError, match="Google Cloud SDK not found"):
+                call_helper(vertex_base)