diff --git a/fix_includes.py b/fix_includes.py
index c5ff2fb..db6d933 100755
--- a/fix_includes.py
+++ b/fix_includes.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 ##===--- fix_includes.py - rewrite source files based on iwyu output ------===##
 #
diff --git a/fix_includes_test.py b/fix_includes_test.py
index f9413f9..009f5ce 100755
--- a/fix_includes_test.py
+++ b/fix_includes_test.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 ##===--- fix_includes_test.py - test for fix_includes.py ------------------===##
 #
diff --git a/iwyu-check-license-header.py b/iwyu-check-license-header.py
index 3651147..13f3a6e 100755
--- a/iwyu-check-license-header.py
+++ b/iwyu-check-license-header.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 ##===--- iwyu-check-license-header.py - check license headers -------------===##
 #
diff --git a/iwyu_test_util.py b/iwyu_test_util.py
index f117d66..69bb781 100755
--- a/iwyu_test_util.py
+++ b/iwyu_test_util.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 ##===--- iwyu_test_util.py - include-what-you-use test framework ----------===##
 #
diff --git a/iwyu_tool.py b/iwyu_tool.py
index fcb210e..0b40db5 100755
--- a/iwyu_tool.py
+++ b/iwyu_tool.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 ##===--- iwyu_tool.py -----------------------------------------------------===##
 #
diff --git a/iwyu_tool_test.py b/iwyu_tool_test.py
index 6d0864b..a48149c 100755
--- a/iwyu_tool_test.py
+++ b/iwyu_tool_test.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 ##===--- iwyu_tool_test.py - test for iwyu_tool.py ------------------------===##
 #
diff --git a/mapgen/iwyu-mapgen-cpython.py b/mapgen/iwyu-mapgen-cpython.py
index cdbcb85..ef5ad63 100755
--- a/mapgen/iwyu-mapgen-cpython.py
+++ b/mapgen/iwyu-mapgen-cpython.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 ##===--- iwyu-mapgen-cpython.py -------------------------------------------===##
 #
diff --git a/mapgen/iwyu-mapgen-qt.py b/mapgen/iwyu-mapgen-qt.py
index 0fca4ad..0a6022b 100755
--- a/mapgen/iwyu-mapgen-qt.py
+++ b/mapgen/iwyu-mapgen-qt.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 ##===--- iwyu-mapgen-qt.py ------------------------------------------------===##
 #
diff --git a/run_iwyu_tests.py b/run_iwyu_tests.py
index 1eeb139..f19fc42 100755
--- a/run_iwyu_tests.py
+++ b/run_iwyu_tests.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 ##===--- run_iwyu_tests.py - include-what-you-use test framework driver ---===##
 #
@@ -52,7 +52,7 @@ def TestIwyuOnRelevantFiles(filename):
                glob.glob('%s/*/%s-*' % (dirname, basename)) +
                glob.glob('%s.h' % all_but_extension) +
                glob.glob('%s/*/%s.h' % (dirname, basename)))
-  
+
   files_to_check = [f for f in all_files if not f.endswith(extension)]
   files_to_check.append(filename)
 
diff --git a/scrub-logs.py b/scrub-logs.py
index b289ea3..aaa7e00 100755
--- a/scrub-logs.py
+++ b/scrub-logs.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
 ##===--- scrub-logs.py - generate README from Wiki sources ----------------===##
 #