diff --git a/__tests__/setup-go.test.ts b/__tests__/setup-go.test.ts
index c241364..6cb16ff 100644
--- a/__tests__/setup-go.test.ts
+++ b/__tests__/setup-go.test.ts
@@ -559,9 +559,31 @@ describe('setup-go', () => {
     expect(im.makeSemver('1.13.1')).toBe('1.13.1');
   });
 
-  describe('go-version-from-file', () => {
-    it('reads version from file', async () => {
-      inputs['go-version-from-file'] = '.go-version';
+  describe('go-version-file', () => {
+    it('reads version from go.mod', async () => {
+      inputs['go-version-file'] = 'go.mod';
+      const content = `module example.com/mymodule
+
+go 1.14
+
+require (
+	example.com/othermodule v1.2.3
+	example.com/thismodule v1.2.3
+	example.com/thatmodule v1.2.3
+)
+
+replace example.com/thatmodule => ../thatmodule
+exclude example.com/thismodule v1.3.0
+`;
+      readFileSpy.mockImplementation(() => Buffer.from(content));
+
+      await main.run();
+
+      expect(logSpy).toHaveBeenCalledWith('Setup go stable version spec 1.14');
+    });
+
+    it('reads version from .go-version', async () => {
+      inputs['go-version-file'] = '.go-version';
       readFileSpy.mockImplementation(() => Buffer.from(`1.13.0${osm.EOL}`));
 
       await main.run();
@@ -573,8 +595,7 @@ describe('setup-go', () => {
 
     it('is overwritten by go-version', async () => {
       inputs['go-version'] = '1.13.1';
-
-      inputs['go-version-from-file'] = '.go-version';
+      inputs['go-version-file'] = '.go-version';
       readFileSpy.mockImplementation(() => Buffer.from(`1.13.0${osm.EOL}`));
 
       await main.run();
@@ -586,7 +607,7 @@ describe('setup-go', () => {
 
     it('reports a read failure', async () => {
       const versionFilePath = '.go-version';
-      inputs['go-version-from-file'] = versionFilePath;
+      inputs['go-version-file'] = versionFilePath;
       const errMsg = `ENOENT: no such file or directory, open '${versionFilePath}'`;
       readFileSpy.mockImplementation(() => {
         throw new Error(errMsg);
diff --git a/dist/index.js b/dist/index.js
index aacd1ca..cb4de94 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -1432,13 +1432,7 @@ function run() {
             // versionSpec is optional.  If supplied, install / use from the tool cache
             // If not supplied then problem matchers will still be setup.  Useful for self-hosted.
             //
-            const versionFilePath = core.getInput('go-version-from-file');
-            const versionSpecFromFile = versionFilePath &&
-                fs_1.default
-                    .readFileSync(versionFilePath)
-                    .toString()
-                    .trim();
-            let versionSpec = core.getInput('go-version') || versionSpecFromFile;
+            const versionSpec = resolveVersionInput();
             // stable will be true unless false is the exact input
             // since getting unstable versions should be explicit
             let stable = (core.getInput('stable') || 'true').toUpperCase() === 'TRUE';
@@ -1506,6 +1500,17 @@ function isGhes() {
     const ghUrl = new url_1.URL(process.env['GITHUB_SERVER_URL'] || 'https://github.com');
     return ghUrl.hostname.toUpperCase() !== 'GITHUB.COM';
 }
+function resolveVersionInput() {
+    let version = core.getInput('go-version');
+    const versionFilePath = core.getInput('go-version-file');
+    if (version) {
+        return version;
+    }
+    if (versionFilePath) {
+        version = installer.parseGoVersionFile(fs_1.default.readFileSync(versionFilePath).toString(), path_1.default.basename(versionFilePath) === 'go.mod');
+    }
+    return version;
+}
 
 
 /***/ }),
@@ -4941,7 +4946,7 @@ var __importDefault = (this && this.__importDefault) || function (mod) {
     return (mod && mod.__esModule) ? mod : { "default": mod };
 };
 Object.defineProperty(exports, "__esModule", { value: true });
-exports.makeSemver = exports.getVersionsDist = exports.findMatch = exports.getInfoFromManifest = exports.extractGoArchive = exports.getGo = void 0;
+exports.parseGoVersionFile = exports.makeSemver = exports.getVersionsDist = exports.findMatch = exports.getInfoFromManifest = exports.extractGoArchive = exports.getGo = void 0;
 const tc = __importStar(__webpack_require__(533));
 const core = __importStar(__webpack_require__(470));
 const path = __importStar(__webpack_require__(622));
@@ -5144,6 +5149,14 @@ function makeSemver(version) {
     return `${verPart}${prereleasePart}`;
 }
 exports.makeSemver = makeSemver;
+function parseGoVersionFile(contents, isMod) {
+    if (!isMod) {
+        return contents.trim();
+    }
+    const match = contents.match(/^go (\d+(\.\d+)*)/m);
+    return match ? match[1] : '';
+}
+exports.parseGoVersionFile = parseGoVersionFile;
 
 
 /***/ }),
diff --git a/src/installer.ts b/src/installer.ts
index 08758a4..bb0a084 100644
--- a/src/installer.ts
+++ b/src/installer.ts
@@ -266,3 +266,12 @@ export function makeSemver(version: string): string {
 
   return `${verPart}${prereleasePart}`;
 }
+
+export function parseGoVersionFile(contents: string, isMod: boolean): string {
+  if (!isMod) {
+    return contents.trim();
+  }
+
+  const match = contents.match(/^go (\d+(\.\d+)*)/m);
+  return match ? match[1] : '';
+}
diff --git a/src/main.ts b/src/main.ts
index 7593e7a..d91c19a 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -12,14 +12,7 @@ export async function run() {
     // versionSpec is optional.  If supplied, install / use from the tool cache
     // If not supplied then problem matchers will still be setup.  Useful for self-hosted.
     //
-    const versionFilePath = core.getInput('go-version-from-file');
-    const versionSpecFromFile =
-      versionFilePath &&
-      fs
-        .readFileSync(versionFilePath)
-        .toString()
-        .trim();
-    let versionSpec = core.getInput('go-version') || versionSpecFromFile;
+    const versionSpec = resolveVersionInput();
 
     // stable will be true unless false is the exact input
     // since getting unstable versions should be explicit
@@ -97,3 +90,21 @@ function isGhes(): boolean {
   );
   return ghUrl.hostname.toUpperCase() !== 'GITHUB.COM';
 }
+
+function resolveVersionInput(): string {
+  let version = core.getInput('go-version');
+  const versionFilePath = core.getInput('go-version-file');
+
+  if (version) {
+    return version;
+  }
+
+  if (versionFilePath) {
+    version = installer.parseGoVersionFile(
+      fs.readFileSync(versionFilePath).toString(),
+      path.basename(versionFilePath) === 'go.mod'
+    );
+  }
+
+  return version;
+}