diff --git a/test/core/end2end/gen_build_json.py b/test/core/end2end/gen_build_json.py
index 2c4368fe767..e28dbdb85d8 100755
--- a/test/core/end2end/gen_build_json.py
+++ b/test/core/end2end/gen_build_json.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python2.7
 
 """Generates the appropriate build.json data for all the end2end tests."""
 
diff --git a/tools/buildgen/mako_renderer.py b/tools/buildgen/mako_renderer.py
index 29c7cf03074..18f6eeaba6c 100755
--- a/tools/buildgen/mako_renderer.py
+++ b/tools/buildgen/mako_renderer.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python2.7
 
 """Simple Mako renderer.
 
diff --git a/tools/run_tests/run_tests.py b/tools/run_tests/run_tests.py
index 8cc029e3ccf..280c3f05cb9 100755
--- a/tools/run_tests/run_tests.py
+++ b/tools/run_tests/run_tests.py
@@ -1,4 +1,4 @@
-#!/usr/bin/python
+#!/usr/bin/python2.7
 """Run tests in parallel."""
 
 import argparse