diff --git a/lib/spack/spack/__init__.py b/lib/spack/spack/__init__.py
index 6ad9b87ca2..48fa9edb67 100644
--- a/lib/spack/spack/__init__.py
+++ b/lib/spack/spack/__init__.py
@@ -39,7 +39,7 @@
 module_path    = join_path(lib_path, "spack")
 platform_path  = join_path(module_path, 'platforms')
 compilers_path = join_path(module_path, "compilers")
-operating_system_path = join_path(module_path, 'operating_system')
+operating_system_path = join_path(module_path, 'operating_systems')
 test_path      = join_path(module_path, "test")
 hooks_path     = join_path(module_path, "hooks")
 var_path       = join_path(prefix, "var", "spack")