diff --git a/docs/requirements.txt b/docs/requirements.txt
index c85e9f1..8b8bccd 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -2,6 +2,7 @@
 sphinx
 sphinx_rtd_theme
 nbsphinx
+sphinx_argparse
 
 # Also requires `brew install pandoc` on Mac
 pandoc