diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 981eb40..75ed433 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -8,8 +8,8 @@ on:
 
 jobs:
   install:
-    name: Rust ${{matrix.rust}}
-    runs-on: ubuntu-latest
+    name: Rust ${{matrix.rust}} ${{matrix.os}}
+    runs-on: ${{matrix.os}}
     strategy:
       fail-fast: false
       matrix:
@@ -23,6 +23,11 @@ jobs:
           "beta",
           "stable",
         ]
+        os: [
+          "ubuntu-latest",
+          "windows-latest",
+          "macos-latest",
+        ]
     steps:
       - uses: actions/checkout@v3
       # Test toolchain file support
diff --git a/action.yml b/action.yml
index fd9e0c2..3a4177b 100644
--- a/action.yml
+++ b/action.yml
@@ -44,6 +44,13 @@ outputs:
 runs:
   using: composite
   steps:
+    # The later code uses "newer" bash features, which are not available in the ancient bash 3 (from 2014) of macOS
+    - name: Unbork mac
+      if: runner.os == 'macOS'
+      run: |
+        brew install bash
+      shell: bash
+
     - id: flags
       run: |
         : construct rustup command line