diff --git a/doc/rtd-requirements.txt b/doc/rtd-requirements.txt
index 3a628c80..15ab89dd 100644
--- a/doc/rtd-requirements.txt
+++ b/doc/rtd-requirements.txt
@@ -1,2 +1,3 @@
 jinja2>3.1
 sphinx-toolbox
+sphinx-rtd-theme>=1.3