diff --git a/bin/spack b/bin/spack
index 0a6d8083424..8386adaa377 100755
--- a/bin/spack
+++ b/bin/spack
@@ -1,7 +1,9 @@
-#!/usr/bin/env python2.7
+#!/usr/bin/env python
+import sys
+if not sys.version_info[:2] >= (2,7):
+    sys.exit("Spack requires Python 2.7.  Version was %s." % sys.version_info)
 
 import os
-import sys
 import argparse
 
 # Find spack's location and its prefix.
diff --git a/lib/spack/env/cc b/lib/spack/env/cc
index 9fa1a185731..0245e065310 100755
--- a/lib/spack/env/cc
+++ b/lib/spack/env/cc
@@ -1,5 +1,8 @@
 #!/usr/bin/env python
 import sys
+if not sys.version_info[:2] >= (2,7):
+    sys.exit("Spack requires Python 2.7.  Version was %s." % sys.version_info)
+
 import os
 import re
 import subprocess