diff --git a/docs/requirements.txt b/docs/requirements.txt
index 32b3ad7..ab6568e 100644
--- a/docs/requirements.txt
+++ b/docs/requirements.txt
@@ -1,6 +1,7 @@
 sphinx==5.0
 sphinx-panels
 sphinxemoji==0.1.8
+sphinx_rtd_theme
 sphinx-copybutton
 m2r2
 mistune==0.8.4