diff --git a/docs/environment.yml b/docs/environment.yml
index fae83078..54420340 100644
--- a/docs/environment.yml
+++ b/docs/environment.yml
@@ -3,7 +3,7 @@ channels:
   - conda-forge
   - conda
 dependencies:
-  - python=3
+  - python==3.5
   - ipython_genutils
   - sphinx
   - sphinx_rtd_theme