diff --git a/openformats/formats/json.py b/openformats/formats/json.py
index 1fcb9a59..8f60333c 100644
--- a/openformats/formats/json.py
+++ b/openformats/formats/json.py
@@ -1,3 +1,5 @@
+# -*- coding: utf-8 -*-
+
 from __future__ import absolute_import
 
 import json
@@ -255,12 +257,30 @@ def _get_next_string(self):
 
     @staticmethod
     def escape(string):
-        escaped_string = string.replace('\\', r'\\').replace('"', '\\"')
-
+        try:
+            # We assume string is unicode and unescaped, eg u'θ':
+            # - First we convert to unicode-escaped-string, eg '\u03b8'
+            # - Then we convert back to unicode, using ascii; unicode-escaped
+            #   strings are always ascii
+            # - unicode_escape will take care of escaping the backslashes (\),
+            #   we only need to escape the double quotes after that
+            escaped_string = string.encode('unicode_escape').decode('ascii')
+        except (UnicodeEncodeError, UnicodeDecodeError):
+            escaped_string = string.replace('\\', r'\\')
+
+        escaped_string = escaped_string.replace('"', '\\"')
         return escaped_string
 
     @staticmethod
     def unescape(string):
-        unescaped_string = string.replace(r'\\', '\\').replace(r'\"', '"')
-
+        try:
+            # We assume string is unicode and unicode-escaped, eg u'\u03b8'
+            # - First we convert it to str, using ascii; unicode-escaped
+            #   strings are always ascii
+            # - Then we convert it to unicode, unescaped, eg 'θ'
+            unescaped_string = string.encode('ascii').decode('unicode_escape')
+        except (UnicodeEncodeError, UnicodeDecodeError):
+            unescaped_string = string.replace(r'\\', '\\')
+
+        unescaped_string = unescaped_string.replace(r'\"', '"')
         return unescaped_string
diff --git a/openformats/tests/formats/beta_keyvaluejson/test_json.py b/openformats/tests/formats/beta_keyvaluejson/test_json.py
index 1b3874e5..4c1b91f9 100644
--- a/openformats/tests/formats/beta_keyvaluejson/test_json.py
+++ b/openformats/tests/formats/beta_keyvaluejson/test_json.py
@@ -1,3 +1,6 @@
+# -*- coding: utf-8 -*-
+
+import json
 import unittest
 
 from openformats.strings import OpenString
@@ -320,8 +323,20 @@ def test_escape_json(self):
             "a \\\\ string. with \\\"quotes\\\""
         )
 
+        self.assertEqual(self.handler.escape(u'καλημέρα'),
+                         self._escape_with_json(u'καλημέρα'))
+
     def test_unescape_json(self):
         self.assertEqual(
             self.handler.unescape("a \\\\ string. with \\\"quotes\\\""),
             "a \\ string. with \"quotes\""
         )
+
+        self.assertEqual(
+            self.handler.unescape(self._escape_with_json(u'καλημέρα')),
+            u'καλημέρα'
+        )
+
+    @staticmethod
+    def _escape_with_json(s):
+        return json.dumps(s)[1:-1].decode()