diff --git a/docs/source/conf.py b/docs/source/conf.py
index ffd223579..799ba1222 100644
--- a/docs/source/conf.py
+++ b/docs/source/conf.py
@@ -31,7 +31,7 @@
 release = coffea.__version__
 githash = subprocess.check_output(["git", "rev-parse", "HEAD"]).strip().decode("ascii")
 
-language = None
+language = "en"
 
 # -- General configuration ---------------------------------------------------