diff --git a/jedi/evaluate/compiled/access.py b/jedi/evaluate/compiled/access.py
index 7d2e6809..e28fd994 100644
--- a/jedi/evaluate/compiled/access.py
+++ b/jedi/evaluate/compiled/access.py
@@ -9,6 +9,7 @@ from jedi._compatibility import unicode, is_py3, builtins, \
     py_version, force_unicode
 from jedi.evaluate.compiled.getattr_static import getattr_static
 
+ALLOWED_GETITEM_TYPES = (str, list, tuple, unicode, bytes, bytearray, dict)
 
 MethodDescriptorType = type(str.replace)
 # These are not considered classes and access is granted even though they have
@@ -226,7 +227,7 @@ class DirectObjectAccess(object):
         return self.py__iter__list()
 
     def py__simple_getitem__(self, index):
-        if type(self._obj) not in (str, list, tuple, unicode, bytes, bytearray, dict):
+        if type(self._obj) not in ALLOWED_GETITEM_TYPES:
             # Get rid of side effects, we won't call custom `__getitem__`s.
             return None
 
@@ -236,7 +237,7 @@ class DirectObjectAccess(object):
         if not hasattr(self._obj, '__getitem__'):
             return None
 
-        if type(self._obj) not in (str, list, tuple, unicode, bytes, bytearray, dict):
+        if type(self._obj) not in ALLOWED_GETITEM_TYPES:
             # Get rid of side effects, we won't call custom `__getitem__`s.
             return []
 
diff --git a/jedi/evaluate/compiled/mixed.py b/jedi/evaluate/compiled/mixed.py
index 474c9951..9146830f 100644
--- a/jedi/evaluate/compiled/mixed.py
+++ b/jedi/evaluate/compiled/mixed.py
@@ -12,10 +12,12 @@ from jedi.evaluate import compiled
 from jedi.cache import underscore_memoization
 from jedi.file_io import FileIO
 from jedi.evaluate.base_context import ContextSet, ContextWrapper
+from jedi.evaluate.helpers import SimpleGetItemNotFound
 from jedi.evaluate.context import ModuleContext
 from jedi.evaluate.cache import evaluator_function_cache
 from jedi.evaluate.compiled.getattr_static import getattr_static
-from jedi.evaluate.compiled.access import compiled_objects_cache
+from jedi.evaluate.compiled.access import compiled_objects_cache, \
+    ALLOWED_GETITEM_TYPES
 from jedi.evaluate.compiled.context import create_cached_compiled_object
 from jedi.evaluate.gradual.conversion import to_stub
 
@@ -56,6 +58,12 @@ class MixedObject(ContextWrapper):
         else:
             return self.compiled_object.get_safe_value(default)
 
+    def py__simple_getitem__(self, index):
+        python_object = self.compiled_object.access_handle.access._obj
+        if type(python_object) in ALLOWED_GETITEM_TYPES:
+            return self.compiled_object.py__simple_getitem__(index)
+        raise SimpleGetItemNotFound
+
     def __repr__(self):
         return '<%s: %s>' % (
             type(self).__name__,
diff --git a/test/test_api/test_interpreter.py b/test/test_api/test_interpreter.py
index cb44bb9c..1bf73713 100644
--- a/test/test_api/test_interpreter.py
+++ b/test/test_api/test_interpreter.py
@@ -176,7 +176,6 @@ def test_getattr():
     _assert_interpreter_complete('getattr(Foo1, baz).app', locals(), ['append'])
 
 
-@pytest.mark.xfail(reason='For now slicing on strings is not supported for mixed objects')
 def test_slice():
     class Foo1:
         bar = []