diff --git a/packages/google-auth/google/auth/transport/__init__.py b/packages/google-auth/google/auth/transport/__init__.py
index 4575763500b2..f3d3c0c4b3a5 100644
--- a/packages/google-auth/google/auth/transport/__init__.py
+++ b/packages/google-auth/google/auth/transport/__init__.py
@@ -24,6 +24,18 @@
 for the return value of :class:`Request`.
 """
 
+__lazy_modules__ = {
+    "google.auth.transport.aiohttp_requests",
+    "google.auth.transport._custom_tls_signer",
+    "google.auth.transport._http_client",
+    "google.auth.transport._mtls_helper",
+    "google.auth.transport._requests_base",
+    "google.auth.transport.grpc",
+    "google.auth.transport.mtls",
+    "google.auth.transport.requests",
+    "google.auth.transport.urllib3",
+}
+
 import abc
 import http.client as http_client