diff --git a/infra/config/PRESUBMIT.py b/infra/config/PRESUBMIT.py
index 6aa75c7df5..b1112937e3 100644
--- a/infra/config/PRESUBMIT.py
+++ b/infra/config/PRESUBMIT.py
@@ -6,6 +6,8 @@
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
+USE_PYTHON3 = True
+
 
 def CheckChangeOnUpload(input_api, output_api):
   return input_api.RunTests(