diff --git a/jingo/helpers.py b/jingo/helpers.py
index fa65206..a2d8eb7 100644
--- a/jingo/helpers.py
+++ b/jingo/helpers.py
@@ -33,9 +33,11 @@ def nl2br(string):
 
 
 @register.filter
-def datetime(t, format=_('%B %e, %Y')):
+def datetime(t, fmt=None):
     """Call ``datetime.strftime`` with the given format string."""
-    return t.strftime(format) if t else ''
+    if fmt is None:
+        fmt = _('%B %e, %Y')
+    return t.strftime(fmt.encode('utf-8')) if t else ''
 
 
 @register.filter
diff --git a/jingo/tests/test_helpers.py b/jingo/tests/test_helpers.py
index 6faf998..90b2077 100644
--- a/jingo/tests/test_helpers.py
+++ b/jingo/tests/test_helpers.py
@@ -1,9 +1,11 @@
+# -*- coding: utf-8 -*-
 """Tests for the jingo's builtin helpers."""
 from datetime import datetime
 
 from nose.tools import eq_
 
 import jingo
+from jingo import helpers
 
 
 def render(s, context={}):
@@ -38,6 +40,11 @@ def test_datetime():
     eq_(s, '')
 
 
+def test_datetime_unicode():
+    fmt = u"%Y 年 %m 月 %e 日"
+    helpers.datetime(datetime.now(), fmt)
+
+
 def test_ifeq():
     eq_context = {'a': 1, 'b': 1}
     neq_context = {'a': 1, 'b': 2}