diff --git a/docs/requirements.txt b/docs/requirements.txt
index fd4795e..1681aa2 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,5 +1,5 @@
 virtualenv
-Sphinx
+Sphinx==1.2.3
 sphinx-rtd-theme
 alabaster!=0.7.5
 setuptools