diff --git a/lib/spack/spack/build_systems/python.py b/lib/spack/spack/build_systems/python.py
index d9563993a93..c6293847b44 100644
--- a/lib/spack/spack/build_systems/python.py
+++ b/lib/spack/spack/build_systems/python.py
@@ -18,6 +18,7 @@
 from llnl.util.filesystem import HeaderList, LibraryList, join_path
 
 import spack.builder
+import spack.build_environment
 import spack.config
 import spack.context
 import spack.deptypes as dt