diff --git a/lib/spack/spack/build_systems/python.py b/lib/spack/spack/build_systems/python.py
index 26166427321..83b50d6b375 100644
--- a/lib/spack/spack/build_systems/python.py
+++ b/lib/spack/spack/build_systems/python.py
@@ -252,7 +252,7 @@ def install_args(self, spec, prefix):
                  '--install-purelib=%s' % pure_site_packages_dir,
                  '--install-platlib=%s' % plat_site_packages_dir,
                  '--install-scripts=bin',
-                 '--install-data=""',
+                 '--install-data=',
                  '--install-headers=%s' % inc_dir
                  ]