diff --git a/requirements.txt b/requirements.txt
index baf0855e8..733413b8c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -19,6 +19,7 @@ gunicorn==19.6.0
 docopt==0.6.2
 six==1.10.0
 iso8601==0.1.12
+celery==3.1.25
 
 # pin to minor version 3.1.x
 notifications-python-client>=3.1,<3.2