diff --git a/google/oauth2/service_account.py b/google/oauth2/service_account.py
index 8f18f26ea..dd3658994 100644
--- a/google/oauth2/service_account.py
+++ b/google/oauth2/service_account.py
@@ -80,7 +80,6 @@
 from google.oauth2 import _client
 
 _DEFAULT_TOKEN_LIFETIME_SECS = 3600  # 1 hour in seconds
-_GOOGLE_OAUTH2_TOKEN_ENDPOINT = "https://oauth2.googleapis.com/token"
 
 
 class Credentials(
@@ -383,7 +382,7 @@ def _make_authorization_grant_assertion(self):
             # The issuer must be the service account email.
             "iss": self._service_account_email,
             # The audience must be the auth token endpoint's URI
-            "aud": _GOOGLE_OAUTH2_TOKEN_ENDPOINT,
+            "aud": self._token_uri,
             "scope": _helpers.scopes_to_string(self._scopes or ()),
         }
 
@@ -644,7 +643,7 @@ def _make_authorization_grant_assertion(self):
             # The issuer must be the service account email.
             "iss": self.service_account_email,
             # The audience must be the auth token endpoint's URI
-            "aud": _GOOGLE_OAUTH2_TOKEN_ENDPOINT,
+            "aud": self._token_uri,
             # The target audience specifies which service the ID token is
             # intended for.
             "target_audience": self._target_audience,
diff --git a/tests/oauth2/test_service_account.py b/tests/oauth2/test_service_account.py
index 370438f48..5852d3714 100644
--- a/tests/oauth2/test_service_account.py
+++ b/tests/oauth2/test_service_account.py
@@ -167,7 +167,7 @@ def test__make_authorization_grant_assertion(self):
         token = credentials._make_authorization_grant_assertion()
         payload = jwt.decode(token, PUBLIC_CERT_BYTES)
         assert payload["iss"] == self.SERVICE_ACCOUNT_EMAIL
-        assert payload["aud"] == service_account._GOOGLE_OAUTH2_TOKEN_ENDPOINT
+        assert payload["aud"] == self.TOKEN_URI
 
     def test__make_authorization_grant_assertion_scoped(self):
         credentials = self.make_credentials()
@@ -440,7 +440,7 @@ def test__make_authorization_grant_assertion(self):
         token = credentials._make_authorization_grant_assertion()
         payload = jwt.decode(token, PUBLIC_CERT_BYTES)
         assert payload["iss"] == self.SERVICE_ACCOUNT_EMAIL
-        assert payload["aud"] == service_account._GOOGLE_OAUTH2_TOKEN_ENDPOINT
+        assert payload["aud"] == self.TOKEN_URI
         assert payload["target_audience"] == self.TARGET_AUDIENCE
 
     @mock.patch("google.oauth2._client.id_token_jwt_grant", autospec=True)
diff --git a/tests_async/oauth2/test_service_account_async.py b/tests_async/oauth2/test_service_account_async.py
index 3dce13d82..40794536c 100644
--- a/tests_async/oauth2/test_service_account_async.py
+++ b/tests_async/oauth2/test_service_account_async.py
@@ -152,10 +152,7 @@ def test__make_authorization_grant_assertion(self):
         token = credentials._make_authorization_grant_assertion()
         payload = jwt.decode(token, test_service_account.PUBLIC_CERT_BYTES)
         assert payload["iss"] == self.SERVICE_ACCOUNT_EMAIL
-        assert (
-            payload["aud"]
-            == service_account.service_account._GOOGLE_OAUTH2_TOKEN_ENDPOINT
-        )
+        assert payload["aud"] == self.TOKEN_URI
 
     def test__make_authorization_grant_assertion_scoped(self):
         credentials = self.make_credentials()
@@ -314,10 +311,7 @@ def test__make_authorization_grant_assertion(self):
         token = credentials._make_authorization_grant_assertion()
         payload = jwt.decode(token, test_service_account.PUBLIC_CERT_BYTES)
         assert payload["iss"] == self.SERVICE_ACCOUNT_EMAIL
-        assert (
-            payload["aud"]
-            == service_account.service_account._GOOGLE_OAUTH2_TOKEN_ENDPOINT
-        )
+        assert payload["aud"] == self.TOKEN_URI
         assert payload["target_audience"] == self.TARGET_AUDIENCE
 
     @mock.patch("google.oauth2._client_async.id_token_jwt_grant", autospec=True)