diff --git a/pyproject.toml b/pyproject.toml
index 6f23fa12..63210f70 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -53,6 +53,7 @@ doc = [
   "sphinx-autoapi",
   "lxml",
   "sphinx-icon",
+  "readthedocs-sphinx-ext",
 ]
 
 onnx = [