diff --git a/.readthedocs.yaml b/.readthedocs.yaml
index ff27254a..1cebab8f 100644
--- a/.readthedocs.yaml
+++ b/.readthedocs.yaml
@@ -17,6 +17,6 @@ sphinx:
   configuration: doc/conf.py
   fail_on_warning: true
 
-# If using Sphinx, optionally build your docs in additional formats such as PDF
-# formats:
-#    - pdf
+python:
+  install:
+    - requirements: doc/requirements.txt
diff --git a/doc/requirements.txt b/doc/requirements.txt
new file mode 100644
index 00000000..e1a4488f
--- /dev/null
+++ b/doc/requirements.txt
@@ -0,0 +1 @@
+sphinx-rtd-theme~=1.3.0