diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
new file mode 100644
index 0000000..7410252
--- /dev/null
+++ b/.github/workflows/test.yml
@@ -0,0 +1,40 @@
+name: Test Action
+
+on:
+  pull_request:
+
+jobs:
+  test:
+    name: Test on ${{ matrix.os }} ${{ matrix.arch }}
+    runs-on: ${{ matrix.runner }}
+    strategy:
+      matrix:
+        include:
+          - os: Linux
+            arch: x86_64
+            runner: ubuntu-latest
+          - os: Linux
+            arch: arm64
+            runner: ubuntu-24.04-arm
+          - os: macOS
+            arch: x86_64
+            runner: macos-15-intel
+          - os: macOS
+            arch: arm64
+            runner: macos-latest
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Roc
+        uses: ./
+
+      - name: Check Roc version
+        run: roc version
+
+      - name: Download HelloWorld example
+        run: curl -fsSL -o main.roc https://raw.githubusercontent.com/roc-lang/examples/main/examples/HelloWorld/main.roc
+
+      - name: Run HelloWorld example
+        run: roc main.roc
diff --git a/README.md b/README.md
index ac53aab..3728d3d 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,6 @@
 # Setup Roc
 
-A GitHub Action to download and setup the Roc compiler for Linux x86_64.
+A GitHub Action to download and setup the Roc compiler for Linux and macOS.
 
 ## Usage
 
@@ -12,16 +12,22 @@ TODO
 
 ## Platform Support
 
-This action currently supports:
-- **OS**: Linux
-- **Architecture**: x86_64
+This action supports the following platforms:
+
+| OS | Architecture | Status |
+|----|--------------|--------|
+| Linux | x86_64 | ✅ |
+| Linux | arm64 | ✅ |
+| macOS | x86_64 (Intel) | ✅ |
+| macOS | arm64 (Apple Silicon) | ✅ |
 
 ## What it does
 
-1. Downloads the Roc compiler (`roc-linux_x86_64-alpha4-rolling.tar.gz`) from the official releases
-2. Verifies the SHA256 checksum to ensure file integrity
-3. Extracts the compiler
-4. Adds the Roc executable to the PATH
+1. Detects your operating system and architecture
+2. Downloads the appropriate Roc compiler release for your platform
+3. Verifies the SHA256 checksum to ensure file integrity
+4. Extracts the compiler
+5. Adds the Roc executable to the PATH
 
 ## Security
 
diff --git a/action.yml b/action.yml
index 6081d27..1a6775e 100644
--- a/action.yml
+++ b/action.yml
@@ -12,25 +12,69 @@ runs:
       run: |
         set -euo pipefail
 
-        # Check if running on Linux x86_64
-        if [[ "$OSTYPE" != "linux-gnu"* ]]; then
-          echo "Error: This action currently only supports Linux"
-          exit 1
-        fi
+        # Detect OS and architecture
+        OS=$(uname -s)
+        ARCH=$(uname -m)
 
-        if [[ "$(uname -m)" != "x86_64" ]]; then
-          echo "Error: This action currently only supports x86_64 architecture"
-          exit 1
-        fi
+        echo "Detected OS: $OS"
+        echo "Detected architecture: $ARCH"
+
+        # Determine platform-specific values
+        case "$OS" in
+          Linux)
+            case "$ARCH" in
+              x86_64)
+                PLATFORM="linux_x86_64"
+                EXPECTED_SHA="96e8be05e6f7176433ada74532ff36a62b8dc44c5247a82cdf919f2dadc5178b"
+                DIR_PATTERN="roc_nightly-linux_x86_64-*"
+                SHA_CMD="sha256sum"
+                ;;
+              aarch64|arm64)
+                PLATFORM="linux_arm64"
+                EXPECTED_SHA="95558e2b5564b9f2b19fb29ad7df440d4ef7163dea571ffcd39409ef678ecccf"
+                DIR_PATTERN="roc_nightly-linux_arm64-*"
+                SHA_CMD="sha256sum"
+                ;;
+              *)
+                echo "Error: Unsupported Linux architecture: $ARCH"
+                exit 1
+                ;;
+            esac
+            ;;
+          Darwin)
+            case "$ARCH" in
+              x86_64)
+                PLATFORM="macos_x86_64"
+                EXPECTED_SHA="e8378bdec9fbeaf8f7bae49159a7b43d42050b047375521799984311dcda7078"
+                DIR_PATTERN="roc_nightly-macos_x86_64-*"
+                SHA_CMD="shasum -a 256"
+                ;;
+              arm64)
+                PLATFORM="macos_apple_silicon"
+                EXPECTED_SHA="416fbd983280eda11ac87b0947e27bf0a86d186a94baebeb71e163942bb5bd84"
+                DIR_PATTERN="roc_nightly-macos_apple_silicon-*"
+                SHA_CMD="shasum -a 256"
+                ;;
+              *)
+                echo "Error: Unsupported macOS architecture: $ARCH"
+                exit 1
+                ;;
+            esac
+            ;;
+          *)
+            echo "Error: Unsupported operating system: $OS"
+            exit 1
+            ;;
+        esac
 
         # Download Roc
-        echo "Downloading Roc for Linux x86_64..."
-        curl -fsSL -o roc.tar.gz https://github.com/roc-lang/roc/releases/download/alpha4-rolling/roc-linux_x86_64-alpha4-rolling.tar.gz
+        DOWNLOAD_URL="https://github.com/roc-lang/roc/releases/download/alpha4-rolling/roc-${PLATFORM}-alpha4-rolling.tar.gz"
+        echo "Downloading Roc for $PLATFORM..."
+        curl -fsSL -o roc.tar.gz "$DOWNLOAD_URL"
 
         # Verify SHA256 checksum
         echo "Verifying SHA256 checksum..."
-        EXPECTED_SHA="96e8be05e6f7176433ada74532ff36a62b8dc44c5247a82cdf919f2dadc5178b"
-        ACTUAL_SHA=$(sha256sum roc.tar.gz | awk '{print $1}')
+        ACTUAL_SHA=$($SHA_CMD roc.tar.gz | awk '{print $1}')
 
         if [[ "$ACTUAL_SHA" != "$EXPECTED_SHA" ]]; then
           echo "Error: SHA256 checksum mismatch!"
@@ -48,7 +92,7 @@ runs:
         rm roc.tar.gz
 
         # Find the extracted directory and add to PATH
-        ROC_DIR=$(find . -maxdepth 1 -type d -name "roc_nightly-linux_x86_64-*" | head -n 1)
+        ROC_DIR=$(find . -maxdepth 1 -type d -name "$DIR_PATTERN" | head -n 1)
         if [[ -z "$ROC_DIR" ]]; then
           echo "Error: Could not find extracted Roc directory"
           exit 1