diff --git a/tests/basics/run-tests b/tests/basics/run-tests
index 72e69c2d8e..0037b13045 100755
--- a/tests/basics/run-tests
+++ b/tests/basics/run-tests
@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 
 RM="/bin/rm -f"
-CPYTHON3=python3
+CPYTHON3=python3.3
 MP_PY=../../unix/py
 
 numtests=0