diff --git a/oauthenticator/google.py b/oauthenticator/google.py
index f9d386b1..72ef7bd9 100644
--- a/oauthenticator/google.py
+++ b/oauthenticator/google.py
@@ -4,6 +4,7 @@
 
 import os
 
+import aiohttp
 from jupyterhub.auth import LocalAuthenticator
 from tornado.auth import GoogleOAuth2Mixin
 from tornado.web import HTTPError
@@ -243,7 +244,7 @@ async def update_auth_model(self, auth_model):
 
         user_groups = set()
         if self.allowed_google_groups or self.admin_google_groups:
-            user_groups = self._fetch_member_groups(user_email, user_domain)
+            user_groups = await self._fetch_member_groups(user_email, user_domain)
         # sets are not JSONable, cast to list for auth_state
         user_info["google_groups"] = list(user_groups)
 
@@ -314,7 +315,7 @@ async def check_allowed(self, username, auth_model):
         # users should be explicitly allowed via config, otherwise they aren't
         return False
 
-    def _service_client_credentials(self, scopes, user_email_domain):
+    async def _service_client_credentials(self, scopes, user_email_domain):
         """
         Return a configured service client credentials for the API.
         """
@@ -338,47 +339,28 @@ def _service_client_credentials(self, scopes, user_email_domain):
 
         return credentials
 
-    def _service_client(self, service_name, service_version, credentials, http=None):
+    async def _setup_credentials(self, user_email_domain):
         """
-        Return a configured service client for the API.
+        Set up the service client for Google API.
         """
+        credentials = await self._service_client_credentials(
+            scopes=[f"{self.google_api_url}/auth/admin.directory.group.readonly"],
+            user_email_domain=user_email_domain,
+        )
+
         try:
-            from googleapiclient.discovery import build
+            from google.auth.transport import requests
         except:
             raise ImportError(
-                "Could not import googleapiclient.discovery's build,"
+                "Could not import google.auth.transport's requests,"
                 "you may need to run 'pip install oauthenticator[googlegroups]' or not declare google groups"
             )
 
-        self.log.debug(
-            f"service_name is {service_name}, service_version is {service_version}"
-        )
-
-        return build(
-            serviceName=service_name,
-            version=service_version,
-            credentials=credentials,
-            cache_discovery=False,
-            http=http,
-        )
-
-    def _setup_service(self, user_email_domain, http=None):
-        """
-        Set up the service client for Google API.
-        """
-        credentials = self._service_client_credentials(
-            scopes=[f"{self.google_api_url}/auth/admin.directory.group.readonly"],
-            user_email_domain=user_email_domain,
-        )
-        service = self._service_client(
-            service_name='admin',
-            service_version='directory_v1',
-            credentials=credentials,
-            http=http,
-        )
-        return service
+        request = requests.Request()
+        credentials.refresh(request)
+        return credentials
 
-    def _fetch_member_groups(
+    async def _fetch_member_groups(
         self,
         member_email,
         user_email_domain,
@@ -389,17 +371,22 @@ def _fetch_member_groups(
         """
         Return a set with the google groups a given user/group is a member of, including nested groups if allowed.
         """
-        # FIXME: When this function is used and waiting for web request
-        #        responses, JupyterHub gets blocked from doing other things.
-        #        Ideally the web requests should be made using an async client
-        #        that can be awaited while JupyterHub handles other things.
-        #
-        if not hasattr(self, 'service'):
-            self.service = self._setup_service(user_email_domain, http)
-
-        resp = self.service.groups().list(userKey=member_email).execute()
+        if not hasattr(self, 'credentials'):
+            self.credentials = await self._setup_credentials(user_email_domain)
+
+        headers = {'Authorization': f'Bearer {self.credentials.token}'}
+
+        async with aiohttp.ClientSession() as session:
+            async with session.get(
+                f'https://www.googleapis.com/admin/directory/v1/groups?userKey={member_email}',
+                headers=headers,
+            ) as resp:
+                group_data = await resp.json()
+
         member_groups = {
-            g['email'].split('@')[0] for g in resp.get('groups', []) if g.get('email')
+            g['email'].split('@')[0]
+            for g in group_data.get('groups', [])
+            if g.get('email')
         }
         self.log.debug(f"Fetched groups for {member_email}: {member_groups}")
 
@@ -410,7 +397,7 @@ def _fetch_member_groups(
             for group in member_groups:
                 if group not in processed_groups:
                     processed_groups.add(group)
-                    nested_groups = self._fetch_member_groups(
+                    nested_groups = await self._fetch_member_groups(
                         f"{group}@{user_email_domain}",
                         user_email_domain,
                         http,
diff --git a/oauthenticator/tests/test_google.py b/oauthenticator/tests/test_google.py
index 4c3a9e0c..070de014 100644
--- a/oauthenticator/tests/test_google.py
+++ b/oauthenticator/tests/test_google.py
@@ -3,6 +3,7 @@
 import logging
 import re
 from unittest import mock
+from unittest.mock import AsyncMock
 
 from pytest import fixture, mark, raises
 from traitlets.config import Config
@@ -211,7 +212,7 @@ async def test_google(
     handled_user_model = user_model("user1@example.com", "user1")
     handler = google_client.handler_for_user(handled_user_model)
     with mock.patch.object(
-        authenticator, "_fetch_member_groups", lambda *args: {"group1"}
+        authenticator, "_fetch_member_groups", AsyncMock(return_value={"group1"})
     ):
         auth_model = await authenticator.get_authenticated_user(handler, None)