diff --git a/.github/workflows/test-and-zip-default-themes.yml b/.github/workflows/test-and-zip-default-themes.yml
index a3a354595ec91..51677fa7adcdd 100644
--- a/.github/workflows/test-and-zip-default-themes.yml
+++ b/.github/workflows/test-and-zip-default-themes.yml
@@ -105,7 +105,7 @@ jobs:
   # - Ensures version-controlled files are not modified or deleted.
   test-build-scripts:
     name: Test ${{ matrix.theme }} build script
-    runs-on: ubuntu-latest
+    runs-on: ${{ matrix.os }}
     permissions:
       contents: read
     timeout-minutes: 10
@@ -113,6 +113,11 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
+        os: [
+          'ubuntu-latest',
+          'windows-latest',
+          'macos-latest',
+        ]
         theme: [
             'twentytwentyone',
             'twentytwenty',