diff --git a/lib/fix-bin.js b/lib/fix-bin.js
index 453bd4f..cb54e2f 100644
--- a/lib/fix-bin.js
+++ b/lib/fix-bin.js
@@ -4,6 +4,7 @@ const {
   chmod,
   open,
   readFile,
+  stat,
 } = require('fs/promises')
 
 const execMode = 0o777 & (~process.umask())
@@ -35,7 +36,8 @@ const dos2Unix = file =>
   readFile(file, 'utf8').then(content =>
     writeFileAtomic(file, content.replace(/^(#![^\n]+)\r\n/, '$1\n')))
 
-const fixBin = (file, mode = execMode) => chmod(file, mode)
+const fixBin = (file, mode = execMode) => stat(file)
+  .then(st => (st.mode & mode) === mode ? null : chmod(file, mode))
   .then(() => isWindowsHashbangFile(file))
   .then(isWHB => isWHB ? dos2Unix(file) : null)
 
diff --git a/test/fix-bin.js b/test/fix-bin.js
index e17cde1..69786d0 100644
--- a/test/fix-bin.js
+++ b/test/fix-bin.js
@@ -93,6 +93,26 @@ t.test('custom exec mode', async t => {
     `#!/usr/bin/env node\nconsole.log('hello')\r\n`, 'fixed \\r on hashbang line')
 })
 
+t.test('skip chmod if file already has exec permissions', async t => {
+  const fsMock = {
+    ...fs.promises,
+    chmod: async () => {
+      throw new Error('chmod should not be called')
+    },
+  }
+  const mockedFixBin = requireInject('../lib/fix-bin.js', {
+    'fs/promises': fsMock,
+  })
+
+  const dir = t.testdir({
+    execfile: `#!/usr/bin/env node\nconsole.log('hello')\n`,
+  })
+  chmodSync(`${dir}/execfile`, 0o755)
+  // should not throw even though chmod is mocked to throw
+  await mockedFixBin(`${dir}/execfile`, 0o755)
+  t.equal((statSync(`${dir}/execfile`).mode & 0o755), 0o755 & (~umask), 'still has exec perms')
+})
+
 t.test('custom exec mode in windows', async t => {
   const dir = t.testdir({
     goodhb: `#!/usr/bin/env node\r\nconsole.log('hello')\r\n`,