diff --git a/Core/src/ServiceBuilder.php b/Core/src/ServiceBuilder.php
index 9a5ac3f4f82..8071b2753d5 100644
--- a/Core/src/ServiceBuilder.php
+++ b/Core/src/ServiceBuilder.php
@@ -49,6 +49,8 @@
  *
  * Please note that unless otherwise noted the examples below take advantage of
  * [Application Default Credentials](https://developers.google.com/identity/protocols/application-default-credentials).
+ *
+ * @deprecated
  */
 class ServiceBuilder
 {