diff --git a/doc-requirements.txt b/doc-requirements.txt
index 9d00def..4a06975 100644
--- a/doc-requirements.txt
+++ b/doc-requirements.txt
@@ -1,4 +1,4 @@
 sphinx>=1.3
 sphinxcontrib-napoleon>=0.4.3
 mock
-sphinx_rtd_theme
+sphinx_rtd_theme==0.5.1