diff --git a/grader_support/gradelib.py b/grader_support/gradelib.py
index 0d05a87..6f16721 100644
--- a/grader_support/gradelib.py
+++ b/grader_support/gradelib.py
@@ -18,7 +18,7 @@ def __init__(self, message=None):
         Exception.__init__(self, message)
 
 
-class Test:
+class Test(object):
     """
     A simple class to wrap a test function and its descriptions.
 
@@ -53,7 +53,7 @@ def compare_results(self, expected, actual):
         return expected == actual
 
 
-class Grader:
+class Grader(object):
     def __init__(self):
         """
         Create an empty grader.
@@ -239,7 +239,7 @@ def _tokens(code):
     """
     # Protect against pathological inputs: http://bugs.python.org/issue16152
     code = code.rstrip() + "\n"
-    if isinstance(code, str):
+    if isinstance(code, six.text_type):
         code = code.encode('utf8')
     code = "# coding: utf8\n" + code
     toks = tokenize.generate_tokens(six.BytesIO(code).readline)
@@ -481,7 +481,7 @@ def exec_wrapped_code(environment=None, post_process=None):
         environment = {}
     def test_fn(submission_module):
         with capture_stdout() as stdout:
-            exec(submission_module.submission_code, environment)
+            six.exec_(submission_module.submission_code, environment)
         stdout_text = stdout.getvalue()
         if post_process:
             stdout_text = post_process(stdout_text)
@@ -503,7 +503,7 @@ def exec_code_and_inspect_values(environment=None, vars_to_inspect=None, post_pr
         environment = {}
     def test_fn(submission_module):
         with capture_stdout() as stdout:
-            exec(submission_module.submission_code, environment)
+            six.exec_(submission_module.submission_code, environment)
 
         for var in vars_to_inspect:
             print(var)
@@ -530,7 +530,7 @@ def invoke_student_function(fn_name, args, environment=None, output_writer=None)
     """
     output_writer = output_writer or repr
     def doit(submission_module):
-        for name, value in environment or {}.items():
+        for name, value in six.iteritems(environment or {}):
             setattr(submission_module, name, value)
         fn = getattr(submission_module, fn_name)
         print(output_writer(fn(*args)))
@@ -543,7 +543,7 @@ class InvokeStudentFunctionTest(Test):
     def __init__(self, fn_name, args, environment=None, output_writer=None, short_desc=None, detailed_desc=None, compare=None):
         test_fn = invoke_student_function(fn_name, args, environment, output_writer)
         if short_desc is None:
-            short_desc = "Test: {}({})".format(fn_name, ", ".join(repr(a) for a in args))
+            short_desc = "Test: %s(%s)" % (fn_name, ", ".join(repr(a) for a in args))
         Test.__init__(self, test_fn, short_desc, detailed_desc, compare)
 
 def round_float_writer(n):
diff --git a/grader_support/graderutil.py b/grader_support/graderutil.py
index aa560c4..ec8fcd2 100644
--- a/grader_support/graderutil.py
+++ b/grader_support/graderutil.py
@@ -37,7 +37,7 @@ def captured_stdout():
         sys.stdout = old_stdout
 
 
-class ChangeDirectory:
+class ChangeDirectory(object):
     def __init__(self, new_dir):
         self.old_dir = os.getcwd()
         os.chdir(new_dir)
@@ -58,7 +58,7 @@ def change_directory(new_dir):
         cd.clean_up()
 
 
-class TempDirectory:
+class TempDirectory(object):
     def __init__(self, delete_when_done=True):
         self.delete_when_done = delete_when_done
         self.temp_dir = tempfile.mkdtemp(prefix="grader-")
@@ -84,7 +84,7 @@ def temp_directory(delete_when_done=True):
         tmp.clean_up()
 
 
-class ModuleIsolation:
+class ModuleIsolation(object):
     """
     Manage changes to sys.modules so that we can roll back imported modules.
 
diff --git a/grader_support/run.py b/grader_support/run.py
index 5323598..9134ac6 100755
--- a/grader_support/run.py
+++ b/grader_support/run.py
@@ -1,4 +1,5 @@
 #!/usr/bin/env python
+# -*- coding: utf-8 -*-
 """
 Run a set of tests on a submission, printing the outputs to stdout as a json
 string.
@@ -30,7 +31,10 @@
     fallback=True,
     languages=[graderutil.LANGUAGE]
 )
-trans.install(names=None)
+if six.PY2:
+    trans.install(names=None, unicode=True)
+else:
+    trans.install(names=None)
 
 
 def run(grader_name, submission_name, seed=1):
diff --git a/load_test/mock_xqueue.py b/load_test/mock_xqueue.py
index fc3928e..49b05d4 100644
--- a/load_test/mock_xqueue.py
+++ b/load_test/mock_xqueue.py
@@ -69,7 +69,7 @@ def get_submission():
     response = {
         'return_code': 0,
         'content': flask.json.dumps({
-            'xqueue_header': '{}.{}'.format(next(counter), idx),
+            'xqueue_header': '{}.{}'.format(counter.next(), idx),
             'xqueue_body': flask.json.dumps({
                 'student_response': submission,
                 'grader_payload': flask.json.dumps(payload)
diff --git a/load_test/run.py b/load_test/run.py
index 0224ae2..35cb4ab 100644
--- a/load_test/run.py
+++ b/load_test/run.py
@@ -29,19 +29,19 @@
 
 def start_mock_xqueue(port):
     cmd = 'gunicorn -w 1 -k gevent -b 0.0.0.0:%s mock_xqueue:app' % port
-    print(cmd)
+    print cmd
     proc = subprocess.Popen(cmd.split())
     return proc
 
 def start_queue_watcher(config_file, codejail_config_file):
     cmd = 'python -m xqueue_watcher -f {} -j {}'.format(config_file, codejail_config_file)
-    print(cmd)
+    print cmd
     proc = subprocess.Popen(cmd.split())
     return proc
 
 def get_stats(server_address):
     pprint.pprint(requests.get('%s/stats' % server_address).json())
-    print('\n')
+    print '\n'
 
 def main(args):
     parser = argparse.ArgumentParser()
@@ -77,7 +77,7 @@ def main(args):
 
         watcher_proc = start_queue_watcher(watcher_config.name, codejail_config.name)
         time.sleep(1)
-        print(requests.get('%s/start' % args.xqueue_address).json())
+        print requests.get('%s/start' % args.xqueue_address).json()
     else:
         watcher_proc = None
 
@@ -97,7 +97,7 @@ def main(args):
     if xqueue_proc:
         os.kill(xqueue_proc.pid, 15)
 
-    print('\n\ndone')
+    print '\n\ndone'
     
 if __name__ == '__main__':
     main(sys.argv[1:])
\ No newline at end of file
diff --git a/xqueue_watcher/client.py b/xqueue_watcher/client.py
index d5935ff..574ebae 100644
--- a/xqueue_watcher/client.py
+++ b/xqueue_watcher/client.py
@@ -10,7 +10,7 @@
 log = logging.getLogger(__name__)
 
 
-class XQueueClient:
+class XQueueClient(object):
     def __init__(self,
                  queue_name,
                  xqueue_server='http://localhost:18040',
@@ -20,7 +20,7 @@ def __init__(self,
                  poll_interval=MANAGER_CONFIG_DEFAULTS['POLL_INTERVAL'],
                  login_poll_interval=MANAGER_CONFIG_DEFAULTS['LOGIN_POLL_INTERVAL'],
                  follow_client_redirects=MANAGER_CONFIG_DEFAULTS['FOLLOW_CLIENT_REDIRECTS']):
-        super().__init__()
+        super(XQueueClient, self).__init__()
         self.session = requests.session()
         self.xqueue_server = xqueue_server
         self.queue_name = queue_name
@@ -97,7 +97,7 @@ def _request(self, method, uri, **kwargs):
                 else:
                     return (False, "Could not log in")
             else:
-                message = "Received un expected response status code, {}, calling {}.".format(
+                message = "Received un expected response status code, {0}, calling {1}.".format(
                     r.status_code,url)
                 log.error(message)
                 return (False, message)
@@ -106,7 +106,7 @@ def _login(self):
         if self.username is None:
             return True
         url = self.xqueue_server + '/xqueue/login/'
-        log.debug("Trying to login to {} with user: {} and pass {}".format(url, self.username, self.password))
+        log.debug("Trying to login to {0} with user: {1} and pass {2}".format(url, self.username, self.password))
         response = self.session.request('post', url, auth=self.http_basic_auth, data={
             'username': self.username,
             'password': self.password,
diff --git a/xqueue_watcher/grader.py b/xqueue_watcher/grader.py
index 0056859..d3b50d6 100644
--- a/xqueue_watcher/grader.py
+++ b/xqueue_watcher/grader.py
@@ -17,9 +17,9 @@ def format_errors(errors):
     error_string = ''
     error_list = [esc(e) for e in errors or []]
     if error_list:
-        items = '\n'.join(['<li><pre>{}</pre></li>\n'.format(e) for e in error_list])
-        error_string = '<ul>\n{}</ul>\n'.format(items)
-        error_string = '<div class="result-errors">{}</div>'.format(error_string)
+        items = '\n'.join(['<li><pre>{0}</pre></li>\n'.format(e) for e in error_list])
+        error_string = '<ul>\n{0}</ul>\n'.format(items)
+        error_string = '<div class="result-errors">{0}</div>'.format(error_string)
     return error_string
 
 
@@ -28,7 +28,7 @@ def to_dict(result):
     # TODO: replace with mako template
     esc = html.escape
     if result[1]:
-        long_desc = '<p>{}</p>'.format(esc(result[1]))
+        long_desc = '<p>{0}</p>'.format(esc(result[1]))
     else:
         long_desc = ''
     return {'short-description': esc(result[0]),
@@ -39,7 +39,7 @@ def to_dict(result):
             }
 
 
-class Grader:
+class Grader(object):
     results_template = """
 <div class="test">
 <header>Test results</header>
@@ -126,10 +126,10 @@ def process_item(self, content, queue=None):
                 # However, for debugging, still want to see what the problem is
                 statsd.increment('xqueuewatcher.grader_payload_error')
 
-                self.log.debug("error parsing: '{}' -- {}".format(payload, err))
+                self.log.debug("error parsing: '{0}' -- {1}".format(payload, err))
                 raise
 
-            self.log.debug("Processing submission, grader payload: {}".format(payload))
+            self.log.debug("Processing submission, grader payload: {0}".format(payload))
             relative_grader_path = grader_config['grader']
             grader_path = (self.grader_root / relative_grader_path).abspath()
             start = time.time()
diff --git a/xqueue_watcher/jailedgrader.py b/xqueue_watcher/jailedgrader.py
index b9c4f45..8bab17f 100644
--- a/xqueue_watcher/jailedgrader.py
+++ b/xqueue_watcher/jailedgrader.py
@@ -18,6 +18,7 @@
 import grader_support
 
 from .grader import Grader
+from six.moves import zip
 
 TIMEOUT = 1
 
@@ -66,7 +67,7 @@ class JailedGrader(Grader):
     """
     def __init__(self, *args, **kwargs):
         self.codejail_python = kwargs.pop("codejail_python", "python")
-        super().__init__(*args, **kwargs)
+        super(JailedGrader, self).__init__(*args, **kwargs)
         self.locale_dir = self.grader_root / "conf" / "locale"
         self.fork_per_item = False  # it's probably safe not to fork
         # EDUCATOR-3368: OpenBLAS library is allowed to allocate 1 thread
@@ -86,7 +87,7 @@ def _run(self, grader_path, thecode, seed):
         return r
 
     def grade(self, grader_path, grader_config, submission):
-        if type(submission) != str:
+        if type(submission) != six.text_type:
             self.log.warning("Submission is NOT unicode")
 
         results = {
@@ -122,7 +123,7 @@ def grade(self, grader_path, grader_config, submission):
         # Import the grader, straight from the original file.  (It probably isn't in
         # sys.path, and we may be in a long running gunicorn process, so we don't
         # want to add stuff to sys.path either.)
-        grader_module = imp.load_source("grader_module", str(grader_path))
+        grader_module = imp.load_source("grader_module", six.text_type(grader_path))
         grader = grader_module.grader
 
         # Preprocess for grader-specified errors
diff --git a/xqueue_watcher/manager.py b/xqueue_watcher/manager.py
index e9c0da1..db64152 100644
--- a/xqueue_watcher/manager.py
+++ b/xqueue_watcher/manager.py
@@ -13,9 +13,10 @@
 from codejail import jail_code
 
 from .settings import get_manager_config_values, MANAGER_CONFIG_DEFAULTS
+from six.moves import range
 
 
-class Manager:
+class Manager(object):
     """
     Manages polling connections to XQueue.
     """