diff --git a/.github/workflows/sphinx.yml b/.github/workflows/sphinx.yml
index c571aa0..dd9c87f 100644
--- a/.github/workflows/sphinx.yml
+++ b/.github/workflows/sphinx.yml
@@ -1,6 +1,10 @@
 name: Sphinx build
 
-on: push
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
 
 jobs:
   build: