diff --git a/autoninja b/autoninja
index 4d1d3fa93..d9c79aa9d 100755
--- a/autoninja
+++ b/autoninja
@@ -5,7 +5,7 @@
 # found in the LICENSE file.
 
 # Set unique build ID.
-AUTONINJA_BUILD_ID="$(python -c "import uuid; print(uuid.uuid4())")"
+AUTONINJA_BUILD_ID="$(vpython -c "import uuid; print(uuid.uuid4())")"
 export AUTONINJA_BUILD_ID
 
 if [ "$NINJA_SUMMARIZE_BUILD" == "1" ]; then