diff --git a/PubSub/src/PubSubClient.php b/PubSub/src/PubSubClient.php
index 67c363bdd7a..fbadc9a2e7a 100644
--- a/PubSub/src/PubSubClient.php
+++ b/PubSub/src/PubSubClient.php
@@ -108,6 +108,9 @@ class PubSubClient
         SchemaServiceClient::class
     ];
 
+    // The name of the service. Used in debug logging.
+    private const SERVICE_NAME = 'google.pubsub.v2.Pubsub';
+
     /**
      * @var RequestHandler
      * @internal