diff --git a/checkout_externals b/checkout_externals
index a0698baef..48bce2401 100755
--- a/checkout_externals
+++ b/checkout_externals
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """Main driver wrapper around the manic/checkout utility.
 
diff --git a/manic/checkout.py b/manic/checkout.py
index 90169bd22..2223b1f0d 100755
--- a/manic/checkout.py
+++ b/manic/checkout.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """
 Tool to assemble repositories represented in a model-description file.
diff --git a/manic/externals_description.py b/manic/externals_description.py
index 42755e1a5..6a5493593 100644
--- a/manic/externals_description.py
+++ b/manic/externals_description.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """Model description
 
diff --git a/manic/utils.py b/manic/utils.py
index f57f43930..9c63ffe65 100644
--- a/manic/utils.py
+++ b/manic/utils.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 """
 Common public utilities for manic package
 
diff --git a/test/test_sys_checkout.py b/test/test_sys_checkout.py
index 9889feba0..b13e96a17 100644
--- a/test/test_sys_checkout.py
+++ b/test/test_sys_checkout.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """Unit test driver for checkout_externals
 
diff --git a/test/test_sys_repository_git.py b/test/test_sys_repository_git.py
index f6dbf8428..29d5433b9 100644
--- a/test/test_sys_repository_git.py
+++ b/test/test_sys_repository_git.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """Tests of some of the functionality in repository_git.py that actually
 interacts with git repositories.
diff --git a/test/test_unit_externals_description.py b/test/test_unit_externals_description.py
index 0b1248f67..30e528849 100644
--- a/test/test_unit_externals_description.py
+++ b/test/test_unit_externals_description.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """Unit test driver for checkout_externals
 
diff --git a/test/test_unit_externals_status.py b/test/test_unit_externals_status.py
index f8e953f75..f019514e9 100644
--- a/test/test_unit_externals_status.py
+++ b/test/test_unit_externals_status.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """Unit test driver for the manic external status reporting module.
 
diff --git a/test/test_unit_repository.py b/test/test_unit_repository.py
index 5b9c242fd..1b9386183 100644
--- a/test/test_unit_repository.py
+++ b/test/test_unit_repository.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """Unit test driver for checkout_externals
 
diff --git a/test/test_unit_repository_git.py b/test/test_unit_repository_git.py
index b153e556a..a6ad9f100 100644
--- a/test/test_unit_repository_git.py
+++ b/test/test_unit_repository_git.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """Unit test driver for checkout_externals
 
diff --git a/test/test_unit_repository_svn.py b/test/test_unit_repository_svn.py
index 7ff31c421..41b173bf3 100644
--- a/test/test_unit_repository_svn.py
+++ b/test/test_unit_repository_svn.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """Unit test driver for checkout_externals
 
diff --git a/test/test_unit_utils.py b/test/test_unit_utils.py
index c994e58eb..80e163664 100644
--- a/test/test_unit_utils.py
+++ b/test/test_unit_utils.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 """Unit test driver for checkout_externals