diff --git a/var/spack/packages/python/package.py b/var/spack/packages/python/package.py
index 920629e9109..eb14c98931f 100644
--- a/var/spack/packages/python/package.py
+++ b/var/spack/packages/python/package.py
@@ -117,7 +117,7 @@ def python_ignore(self, ext_pkg, args):
 
         # Ignore pieces of setuptools installed by other packages.
         if ext_pkg.name != 'py-setuptools':
-            patterns.append(r'/site.*\.pyc?$')
+            patterns.append(r'/site[^/]*\.pyc?$')
             patterns.append(r'setuptools\.pth')
             patterns.append(r'bin/easy_install[^/]*$')
             patterns.append(r'setuptools.*egg$')