diff --git a/setup.py b/setup.py
index e540157..23b3dc3 100644
--- a/setup.py
+++ b/setup.py
@@ -48,6 +48,7 @@ def create_version_file():
     'Pillow',
     'scipy',
     'requests',
+    'portalocker',
 ]
 
 def get_extensions():