diff --git a/bigquery-datatransfer/snippets/requirements-test.txt b/bigquery-datatransfer/snippets/requirements-test.txt
index 1a71e3e3296a..676ff949e8ae 100644
--- a/bigquery-datatransfer/snippets/requirements-test.txt
+++ b/bigquery-datatransfer/snippets/requirements-test.txt
@@ -1,2 +1,2 @@
 pytest==5.4.3
-mock==3.0.5
+mock==4.0.2