diff --git a/index.js b/index.js
index b28bd6e..71a7a56 100644
--- a/index.js
+++ b/index.js
@@ -19,10 +19,36 @@ module.exports = function getOs (cb) {
   var osName = os.platform()
   // Linux is a special case.
   if (osName === 'linux') return getLinuxDistro(cb)
+  if (osName === 'darwin') return getDarwinVersion(cb)
   // Else, node's builtin is acceptable.
   return cb(null, { os: osName })
 }
 
+function getDarwinVersion (cb) {
+  if (cachedDistro) return cb(null, cachedDistro)
+  var productVersionRegex = /^ProductVersion:\s+(.*)/m
+  var productNameRegex = /^ProductName:\s+(.*)/m
+  var exec = require('child_process').exec
+
+  var distro = { os: 'darwin' }
+
+  exec('sw_vers', function (error, stdout, stderr) {
+    if (error) {
+      return cb(error, { os: os.platform() })
+    }
+    var productVersion = stdout.match(productVersionRegex)
+    if (productVersion && productVersion.length === 2) {
+      distro.release = productVersion[1]
+    }
+    var name = stdout.match(productNameRegex)
+    if (name && name.length === 2) {
+      distro.name = name[1]
+    }
+    cachedDistro = distro
+    return cb(null, distro)
+  })
+}
+
 /**
  * Identify the actual distribution name on a linux box.
  */
diff --git a/tests/mockdata.json b/tests/mockdata.json
index c2c2d66..f731e91 100644
--- a/tests/mockdata.json
+++ b/tests/mockdata.json
@@ -1,5 +1,5 @@
 [
-  { "desc": "OS X", "platform": "darwin", "expected": { "os": "darwin" } }
+  { "desc": "OS X", "platform": "darwin", "exec": { "sw_vers": "ProductName:\tmacOS\nProductVersion:\t11.4\nBuildVersion:\t20F71\n"}, "expected": { "os": "darwin", "release": "11.4", "name": "macOS" } }
 , { "desc": "Windows", "platform": "win32", "expected": { "os": "win32"  } }
 , { "desc": "Ubuntu 14.10", "platform": "linux", "file": { "/etc/lsb-release": "DISTRIB_ID=Ubuntu\nDISTRIB_RELEASE=14.10\nDISTRIB_CODENAME=utopic\nDISTRIB_DESCRIPTION=\"Ubuntu 14.10\"\n" },        "expected": { "codename": "utopic", "dist": "Ubuntu", "os": "linux", "release": "14.10" }  }
 , { "desc": "Ubuntu 14.04", "platform": "linux", "file": { "/etc/lsb-release": "DISTRIB_ID=Ubuntu\nDISTRIB_RELEASE=14.04\nDISTRIB_CODENAME=trusty\nDISTRIB_DESCRIPTION=\"Ubuntu 14.04.2 LTS\"\n" },  "expected": { "codename": "trusty", "dist": "Ubuntu", "os": "linux", "release": "14.04" }  }
diff --git a/tests/mocktests.js b/tests/mocktests.js
index aa152d7..64806e6 100644
--- a/tests/mocktests.js
+++ b/tests/mocktests.js
@@ -1,6 +1,7 @@
 var test = require('tape')
 var fs = require('fs')
 var os = require('os')
+var cp = require('child_process')
 var mockdata = require('./mockdata')
 
 var currentData
@@ -23,6 +24,13 @@ fs.readFile = function (file, enc, callback) {
   })
 }
 
+cp.exec = function (command, callback) {
+  process.nextTick(function () {
+    if (!currentData.exec[command]) { return callback(new Error()) }
+    callback(null, currentData.exec[command])
+  })
+}
+
 mockdata.forEach(function (data) {
   test('test ' + data.desc, function (t) {
     // reload each time to avoid internal caching