diff --git a/docs/requirements.txt b/docs/requirements.txt
index ee44a2ca..0e349f9c 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -20,6 +20,7 @@ six==1.11.0
 snowballstemmer==1.2.1
 Sphinx==1.6.3
 sphinx-click==1.3.0
+sphinxcontrib-spelling==4.2.1
 sphinxcontrib-websupport==1.1.0
 urllib3==1.24.1
 virtualenv==16.1.0