diff --git a/ci/msbuild.yml b/ci/msbuild.yml
index 29b6ace..e650e2a 100644
--- a/ci/msbuild.yml
+++ b/ci/msbuild.yml
@@ -1,6 +1,10 @@
 name: MSBuild
 
-on: [push]
+on:
+  push:
+    branches: [ $default-branch ]
+  pull_request:
+    branches: [ $default-branch ]
 
 env:
   # Path to the solution file relative to the root of the project.