diff --git a/docs/environment.yml b/docs/environment.yml
index 316bc7869..9c6999e48 100644
--- a/docs/environment.yml
+++ b/docs/environment.yml
@@ -7,9 +7,9 @@ dependencies:
 - nbformat
 - jupyter_client
 - ipython
-- sphinx>=1.5.1
 - sphinx_rtd_theme
 - tornado
 - entrypoints
 - pip:
+    - sphinx>=1.5.1
     - nbsphinx