diff --git a/var/spack/repos/builtin/packages/doxygen/package.py b/var/spack/repos/builtin/packages/doxygen/package.py
index b2e9582b5a..b65eafb2cd 100644
--- a/var/spack/repos/builtin/packages/doxygen/package.py
+++ b/var/spack/repos/builtin/packages/doxygen/package.py
@@ -24,6 +24,8 @@
 ##############################################################################
 from spack import *
 
+import sys
+
 
 class Doxygen(Package):
     """Doxygen is the de facto standard tool for generating documentation