diff --git a/boto/s3/bucket.py b/boto/s3/bucket.py
index 34514078c2..504f24f9bb 100644
--- a/boto/s3/bucket.py
+++ b/boto/s3/bucket.py
@@ -377,7 +377,9 @@ def _get_all_query_args(self, params, initial_query_string=''):
                 key = 'max-keys'
             if not isinstance(value, six.string_types + (six.binary_type,)):
                 value = six.text_type(value)
-            if value != '':
+            if not isinstance(value, six.binary_type):
+                value = value.encode('utf-8')
+            if value:
                 pairs.append(u'%s=%s' % (
                     urllib.parse.quote(key),
                     urllib.parse.quote(value)
diff --git a/tests/unit/s3/test_bucket.py b/tests/unit/s3/test_bucket.py
index 3dc5f6e3ce..72e10ed2f9 100644
--- a/tests/unit/s3/test_bucket.py
+++ b/tests/unit/s3/test_bucket.py
@@ -92,6 +92,8 @@ def test__get_all_query_args(self):
             'foo': 'true',
             # Ensure Unicode chars get encoded.
             'bar': '☃',
+            # Ensure unicode strings with non-ascii characters get encoded
+            'baz': u'χ',
             # Underscores are bad, m'kay?
             'some_other': 'thing',
             # Change the variant of ``max-keys``.
@@ -104,14 +106,14 @@ def test__get_all_query_args(self):
         qa = bukket._get_all_query_args(multiple_params)
         self.assertEqual(
             qa,
-            'bar=%E2%98%83&foo=true&max-keys=0&some-other=thing'
+            'bar=%E2%98%83&baz=%CF%87&foo=true&max-keys=0&some-other=thing'
         )
 
         # Multiple params with initial.
         qa = bukket._get_all_query_args(multiple_params, 'initial=1')
         self.assertEqual(
             qa,
-            'initial=1&bar=%E2%98%83&foo=true&max-keys=0&some-other=thing'
+            'initial=1&bar=%E2%98%83&baz=%CF%87&foo=true&max-keys=0&some-other=thing'
         )
 
     @patch.object(S3Connection, 'head_bucket')