diff --git a/pyproject.toml b/pyproject.toml
index 4f91871..4d98a22 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -53,8 +53,8 @@ test = [
 ]
 
 doc = [
-  "sphinx",
-  "sphinx-rtd-theme",
+  "sphinx<7",
+  "sphinx-rtd-theme<1.3",
 ]
 
 [project.urls]