diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 5332430..5431e44 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -10,7 +10,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [ubuntu-latest, macos-latest]
+        os: [ubuntu-latest, macos-latest, windows-latest]
         smlnj-version: [110.87, 110.97, 110.98]
         exclude:
           # SML/NJ versions before 110.94 do not support 64-bit
@@ -22,5 +22,12 @@ jobs:
       - uses: ./
         with:
           smlnj-version: ${{ matrix.smlnj-version }}
-      - run: |
+      - name: Test version output (Unix)
+        if: matrix.os != 'windows-latest'
+        run: |
           [[ $(sml @SMLversion) == "sml ${{ matrix.smlnj-version }}" ]]
+      - name: Test version output (Windows)
+        if: matrix.os == 'windows-latest'
+        run: |
+          # "$(sml @SMLversion)" -eq "sml ${{ matrix.smlnj-version }}"
+          Get-Command sml
diff --git a/lib/installer.js b/lib/installer.js
index 5b4f725..0afa7e5 100644
--- a/lib/installer.js
+++ b/lib/installer.js
@@ -38,19 +38,50 @@ function getNJ(version) {
 exports.getNJ = getNJ;
 function acquireNJ(version) {
     return __awaiter(this, void 0, void 0, function* () {
-        if (process.platform === "linux") {
-            // install required 32-bit support libraries
-            yield exec.exec("sudo", ["apt-get", "update"]);
-            yield exec.exec("sudo", [
-                "apt-get",
-                "install",
-                "-y",
-                "--no-install-recommends",
-                "gcc-multilib",
-                "lib32ncurses5",
-                "lib32z1"
-            ]);
+        switch (process.platform) {
+            case "win32":
+                return acquireNJWindows(version);
+            case "linux":
+                return acquireNJLinux(version);
+            default:
+                return acquireNJUnix(version);
         }
+    });
+}
+function acquireNJWindows(version) {
+    return __awaiter(this, void 0, void 0, function* () {
+        let downloadUrl = util.format("https://smlnj.org/dist/working/%s/smlnj-%s.msi", version, version);
+        core.debug("Downloading SML/NJ from: " + downloadUrl);
+        let downloadPath = null;
+        try {
+            downloadPath = yield tc.downloadTool(downloadUrl);
+        }
+        catch (error) {
+            core.debug(error);
+            throw `Failed to download version ${version}: ${error}`;
+        }
+        yield exec.exec("msiexec", ["/qn", "/i", downloadPath]);
+        return new Promise((resolve, _) => resolve(path.join("C:", "Program Files (x86)", "SMLNJ")));
+    });
+}
+function acquireNJLinux(version) {
+    return __awaiter(this, void 0, void 0, function* () {
+        // install required 32-bit support libraries
+        yield exec.exec("sudo", ["apt-get", "update"]);
+        yield exec.exec("sudo", [
+            "apt-get",
+            "install",
+            "-y",
+            "--no-install-recommends",
+            "gcc-multilib",
+            "lib32ncurses5",
+            "lib32z1"
+        ]);
+        return acquireNJUnix(version);
+    });
+}
+function acquireNJUnix(version) {
+    return __awaiter(this, void 0, void 0, function* () {
         let downloadUrl = util.format("http://smlnj.cs.uchicago.edu/dist/working/%s/config.tgz", version);
         core.debug("Downloading SML/NJ from: " + downloadUrl);
         let downloadPath = null;
diff --git a/src/installer.ts b/src/installer.ts
index 054ac70..3e080c1 100644
--- a/src/installer.ts
+++ b/src/installer.ts
@@ -20,20 +20,57 @@ export async function getNJ(version: string) {
 }
 
 async function acquireNJ(version: string): Promise<string> {
-  if (process.platform === "linux") {
-    // install required 32-bit support libraries
-    await exec.exec("sudo", ["apt-get", "update"]);
-    await exec.exec("sudo", [
-      "apt-get",
-      "install",
-      "-y",
-      "--no-install-recommends",
-      "gcc-multilib",
-      "lib32ncurses5",
-      "lib32z1"
-    ]);
+  switch (process.platform) {
+    case "win32":
+      return acquireNJWindows(version);
+    case "linux":
+      return acquireNJLinux(version);
+    default:
+      return acquireNJUnix(version);
   }
+}
+
+async function acquireNJWindows(version: string): Promise<string> {
+  let downloadUrl: string = util.format(
+    "https://smlnj.org/dist/working/%s/smlnj-%s.msi",
+    version,
+    version
+  );
+
+  core.debug("Downloading SML/NJ from: " + downloadUrl);
+
+  let downloadPath: string | null = null;
+  try {
+    downloadPath = await tc.downloadTool(downloadUrl);
+  } catch (error) {
+    core.debug(error);
+
+    throw `Failed to download version ${version}: ${error}`;
+  }
+
+  await exec.exec("msiexec", ["/qn", "/i", downloadPath]);
+  return new Promise((resolve, _) =>
+    resolve(path.join("C:", "Program Files (x86)", "SMLNJ"))
+  );
+}
+
+async function acquireNJLinux(version: string): Promise<string> {
+  // install required 32-bit support libraries
+  await exec.exec("sudo", ["apt-get", "update"]);
+  await exec.exec("sudo", [
+    "apt-get",
+    "install",
+    "-y",
+    "--no-install-recommends",
+    "gcc-multilib",
+    "lib32ncurses5",
+    "lib32z1"
+  ]);
+
+  return acquireNJUnix(version);
+}
 
+async function acquireNJUnix(version: string): Promise<string> {
   let downloadUrl: string = util.format(
     "http://smlnj.cs.uchicago.edu/dist/working/%s/config.tgz",
     version