diff --git a/docs/requirements.txt b/docs/requirements.txt
index 8a8a404..92ff552 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,3 +1,3 @@
 sphinx>=1.3
-sphinx-rtd-theme
+sphinx-rtd-theme==0.2.4
 -e .