diff --git a/testing/xpcshell/head.js b/testing/xpcshell/head.js
index cc86a15ecdf6..9784294a6ecf 100644
--- a/testing/xpcshell/head.js
+++ b/testing/xpcshell/head.js
@@ -1214,6 +1214,7 @@ function do_load_child_test_harness()
   let command =
         "const _HEAD_JS_PATH=" + uneval(_HEAD_JS_PATH) + "; "
       + "const _HEAD_FILES=" + uneval(_HEAD_FILES) + "; "
+      + "const _MOZINFO_JS_PATH=" + uneval(_MOZINFO_JS_PATH) + "; "
       + "const _TAIL_FILES=" + uneval(_TAIL_FILES) + "; "
       + "const _TEST_NAME=" + uneval(_TEST_NAME) + "; "
       // We'll need more magic to get the debugger working in the child
@@ -1519,3 +1520,29 @@ try {
     prefs.deleteBranch("browser.devedition.theme.enabled");
   }
 } catch (e) { }
+
+function _load_mozinfo() {
+  let mozinfoFile = Components.classes["@mozilla.org/file/local;1"]
+    .createInstance(Components.interfaces.nsIFile);
+  mozinfoFile.initWithPath(_MOZINFO_JS_PATH);
+  let stream = Components.classes["@mozilla.org/network/file-input-stream;1"]
+    .createInstance(Components.interfaces.nsIFileInputStream);
+  stream.init(mozinfoFile, -1, 0, 0);
+  let json = Components.classes["@mozilla.org/dom/json;1"]
+    .createInstance(Components.interfaces.nsIJSON);
+  let mozinfo = json.decodeFromStream(stream, stream.available());
+  stream.close();
+  return mozinfo;
+}
+
+Object.defineProperty(this, "mozinfo", {
+  configurable: true,
+  get() {
+    let _mozinfo = _load_mozinfo();
+    Object.defineProperty(this, "mozinfo", {
+      configurable: false,
+      value: _mozinfo
+    });
+    return _mozinfo;
+  }
+});
diff --git a/testing/xpcshell/remotexpcshelltests.py b/testing/xpcshell/remotexpcshelltests.py
index c65caa99bf39..0428804720e7 100644
--- a/testing/xpcshell/remotexpcshelltests.py
+++ b/testing/xpcshell/remotexpcshelltests.py
@@ -71,6 +71,14 @@ class RemoteXPCShellTestThread(xpcshell.XPCShellTestThread):
             self.log.info("profile dir is %s" % self.profileDir)
         return self.profileDir
 
+    def setupMozinfoJS(self):
+        local = tempfile.mktemp()
+        mozinfo.output_to_file(local)
+        mozInfoJSPath = remoteJoin(self.profileDir, "mozinfo.json")
+        self.device.pushFile(local, mozInfoJSPath)
+        os.remove(local)
+        return mozInfoJSPath
+
     def logCommand(self, name, completeCmd, testdir):
         self.log.info("%s | full command: %r" % (name, completeCmd))
         self.log.info("%s | current directory: %r" % (name, self.remoteHere))
diff --git a/testing/xpcshell/runxpcshelltests.py b/testing/xpcshell/runxpcshelltests.py
index f5335b092b88..7e6e5c67f98e 100755
--- a/testing/xpcshell/runxpcshelltests.py
+++ b/testing/xpcshell/runxpcshelltests.py
@@ -392,6 +392,12 @@ class XPCShellTestThread(Thread):
             self.log.info("profile dir is %s" % profileDir)
         return profileDir
 
+    def setupMozinfoJS(self):
+        mozInfoJSPath = os.path.join(self.profileDir, 'mozinfo.json')
+        mozInfoJSPath = mozInfoJSPath.replace('\\', '\\\\')
+        mozinfo.output_to_file(mozInfoJSPath)
+        return mozInfoJSPath
+
     def buildCmdHead(self, headfiles, tailfiles, xpcscmd):
         """
           Build the command line arguments for the head and tail files,
@@ -456,7 +462,8 @@ class XPCShellTestThread(Thread):
             '-r', self.httpdManifest,
             '-m',
             '-s',
-            '-e', 'const _HEAD_JS_PATH = "%s";' % self.headJSPath
+            '-e', 'const _HEAD_JS_PATH = "%s";' % self.headJSPath,
+            '-e', 'const _MOZINFO_JS_PATH = "%s";' % self.mozInfoJSPath,
         ]
 
         if self.testingModulesDir:
@@ -633,14 +640,16 @@ class XPCShellTestThread(Thread):
             self.appPath = None
 
         test_dir = os.path.dirname(path)
-        self.buildXpcsCmd(test_dir)
-        head_files, tail_files = self.getHeadAndTailFiles(self.test_object)
-        cmdH = self.buildCmdHead(head_files, tail_files, self.xpcsCmd)
 
         # Create a profile and a temp dir that the JS harness can stick
         # a profile and temporary data in
         self.profileDir = self.setupProfileDir()
         self.tempDir = self.setupTempDir()
+        self.mozInfoJSPath = self.setupMozinfoJS()
+
+        self.buildXpcsCmd(test_dir)
+        head_files, tail_files = self.getHeadAndTailFiles(self.test_object)
+        cmdH = self.buildCmdHead(head_files, tail_files, self.xpcsCmd)
 
         # The test file will have to be loaded after the head files.
         cmdT = self.buildCmdTestFile(path)
diff --git a/testing/xpcshell/selftest.py b/testing/xpcshell/selftest.py
index aa54b49fda70..5ed4fe6cf220 100644
--- a/testing/xpcshell/selftest.py
+++ b/testing/xpcshell/selftest.py
@@ -349,7 +349,21 @@ add_task(function test_2() {
 });
 '''
 
+LOAD_MOZINFO = '''
+function run_test() {
+  do_check_neq(typeof mozinfo, undefined);
+  do_check_neq(typeof mozinfo.os, undefined);
+}
+'''
 
+CHILD_MOZINFO = '''
+function run_test () { run_next_test(); }
+
+add_test(function test_child_mozinfo () {
+  run_test_in_child("test_mozinfo.js");
+  run_next_test();
+});
+'''
 class XPCShellTestsTests(unittest.TestCase):
     """
     Yes, these are unit tests for a unit test harness.
@@ -1203,5 +1217,34 @@ add_test({
         self.assertInLog(TEST_PASS_STRING)
         self.assertNotInLog(TEST_FAIL_STRING)
 
+    def testMozinfo(self):
+        """
+        Check that mozinfo.json is loaded
+        """
+        self.writeFile("test_mozinfo.js", LOAD_MOZINFO)
+        self.writeManifest(["test_mozinfo.js"])
+        self.assertTestResult(True)
+        self.assertEquals(1, self.x.testCount)
+        self.assertEquals(1, self.x.passCount)
+        self.assertEquals(0, self.x.failCount)
+        self.assertEquals(0, self.x.todoCount)
+        self.assertInLog(TEST_PASS_STRING)
+        self.assertNotInLog(TEST_FAIL_STRING)
+
+    def testChildMozinfo(self):
+        """
+        Check that mozinfo.json is loaded in child process
+        """
+        self.writeFile("test_mozinfo.js", LOAD_MOZINFO)
+        self.writeFile("test_child_mozinfo.js", CHILD_MOZINFO)
+        self.writeManifest(["test_child_mozinfo.js"])
+        self.assertTestResult(True)
+        self.assertEquals(1, self.x.testCount)
+        self.assertEquals(1, self.x.passCount)
+        self.assertEquals(0, self.x.failCount)
+        self.assertEquals(0, self.x.todoCount)
+        self.assertInLog(TEST_PASS_STRING)
+        self.assertNotInLog(TEST_FAIL_STRING)
+
 if __name__ == "__main__":
     unittest.main(verbosity=3)