diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index c7ce10c..381566a 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -3,13 +3,16 @@ on:
   push:
   pull_request:
   schedule:
-    - cron: '0 10 * * 1' # At 10:00 on Monday.
+    - cron: "0 10 * * 1" # At 10:00 on Monday.
 defaults:
   run:
     shell: pwsh
 jobs:
   build:
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+    runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v2
       - name: Test with Pester
@@ -42,7 +45,10 @@ jobs:
             return 1
           }
   self-testing:
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+    runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v2