diff --git a/docs/readthedocs.requirements.txt b/docs/readthedocs.requirements.txt
index c3dd46e..19d2979 100644
--- a/docs/readthedocs.requirements.txt
+++ b/docs/readthedocs.requirements.txt
@@ -1 +1,2 @@
 sphinx-autoapi==3.0.0
+sphinx-rtd-theme==1.3.0