diff --git a/test/core/end2end/gen_build_json.py b/test/core/end2end/gen_build_json.py
index 2c4368fe767f66e500b8ec525d253c346cb00a3a..e28dbdb85d8edd6f436d670f0302e8b74ba4df78 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 29c7cf03074122c660bea52fb9089778986dcf8e..18f6eeaba6c9e4facd458933f3059a437e242b19 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 8cc029e3ccf0c39a41c606e2a16e596d24e0d3e3..280c3f05cb98a726a781df8ca1f099dc648e8a31 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