diff --git a/Lib/plat-mac/bundlebuilder.py b/Lib/plat-mac/bundlebuilder.py
index 9e4fc91..5fe2c60 100755
--- a/Lib/plat-mac/bundlebuilder.py
+++ b/Lib/plat-mac/bundlebuilder.py
@@ -272,6 +272,7 @@
 
 sys.argv.insert(1, mainprogram)
 os.environ["PYTHONPATH"] = resdir
+os.environ["PYTHONHOME"] = resdir
 os.environ["PYTHONEXECUTABLE"] = executable
 os.execve(executable, sys.argv, os.environ)
 """