diff --git a/python/requirements.txt b/python/requirements.txt
index 97487c76aff..51290d7a554 100644
--- a/python/requirements.txt
+++ b/python/requirements.txt
@@ -5,6 +5,7 @@ mozinfo == 0.8
 mozlog == 3.3
 setuptools == 18.5
 toml == 0.9.1
+Mako == 1.0.4
 
 # For Python linting
 flake8 == 2.4.1