diff --git a/docs/rtd_environment.yml b/docs/rtd_environment.yml
index 1e9288d5..7be4441a 100644
--- a/docs/rtd_environment.yml
+++ b/docs/rtd_environment.yml
@@ -2,5 +2,6 @@ name: dpdata
 channels:
   - conda-forge
 dependencies:
+  - python <3.13
   - pip:
     - ..[docs]