diff --git a/run_tests.sh b/run_tests.sh
index 971f89b..9a158e4 100755
--- a/run_tests.sh
+++ b/run_tests.sh
@@ -19,7 +19,7 @@
 
 testrargs=""
 just_pep8=0
-venv=.venv
+venv=${VENV:-.venv}
 with_venv=tools/with_venv.sh
 serial=0
 always_venv=0