diff --git a/Lib/collections/__init__.py b/Lib/collections/__init__.py
index 2eee4c70955513..febab521629228 100644
--- a/Lib/collections/__init__.py
+++ b/Lib/collections/__init__.py
@@ -328,14 +328,14 @@ def __ior__(self, other):
         return self
 
     def __or__(self, other):
-        if not isinstance(other, dict):
+        if not isinstance(other, (dict, frozendict)):
             return NotImplemented
         new = self.__class__(self)
         new.update(other)
         return new
 
     def __ror__(self, other):
-        if not isinstance(other, dict):
+        if not isinstance(other, (dict, frozendict)):
             return NotImplemented
         new = self.__class__(other)
         new.update(self)
@@ -1216,14 +1216,14 @@ def __repr__(self):
     def __or__(self, other):
         if isinstance(other, UserDict):
             return self.__class__(self.data | other.data)
-        if isinstance(other, dict):
+        if isinstance(other, (dict, frozendict)):
             return self.__class__(self.data | other)
         return NotImplemented
 
     def __ror__(self, other):
         if isinstance(other, UserDict):
             return self.__class__(other.data | self.data)
-        if isinstance(other, dict):
+        if isinstance(other, (dict, frozendict)):
             return self.__class__(other | self.data)
         return NotImplemented
 
diff --git a/Lib/test/test_ordered_dict.py b/Lib/test/test_ordered_dict.py
index 4204a6a47d2a81..7963995a575744 100644
--- a/Lib/test/test_ordered_dict.py
+++ b/Lib/test/test_ordered_dict.py
@@ -698,6 +698,7 @@ def test_merge_operator(self):
         d |= list(b.items())
         expected = OrderedDict({0: 0, 1: 1, 2: 2, 3: 3})
         self.assertEqual(a | dict(b), expected)
+        self.assertEqual(a | frozendict(b), expected)
         self.assertEqual(a | b, expected)
         self.assertEqual(c, expected)
         self.assertEqual(d, expected)
@@ -706,12 +707,15 @@ def test_merge_operator(self):
         c |= a
         expected = OrderedDict({1: 1, 2: 1, 3: 3, 0: 0})
         self.assertEqual(dict(b) | a, expected)
+        self.assertEqual(frozendict(b) | a, expected)
         self.assertEqual(b | a, expected)
         self.assertEqual(c, expected)
 
         self.assertIs(type(a | b), OrderedDict)
         self.assertIs(type(dict(a) | b), OrderedDict)
+        self.assertIs(type(frozendict(a) | b), frozendict)  # BUG: should be OrderedDict
         self.assertIs(type(a | dict(b)), OrderedDict)
+        self.assertIs(type(a | frozendict(b)), OrderedDict)
 
         expected = a.copy()
         a |= ()
diff --git a/Lib/test/test_userdict.py b/Lib/test/test_userdict.py
index 13285c9b2a3b7f..c60135ca5a12a8 100644
--- a/Lib/test/test_userdict.py
+++ b/Lib/test/test_userdict.py
@@ -245,7 +245,7 @@ class G(collections.UserDict):
     test_repr_deep = mapping_tests.TestHashMappingProtocol.test_repr_deep
 
     def test_mixed_or(self):
-        for t in UserDict, dict, types.MappingProxyType:
+        for t in UserDict, dict, frozendict, types.MappingProxyType:
             with self.subTest(t.__name__):
                 u = UserDict({0: 'a', 1: 'b'}) | t({1: 'c', 2: 'd'})
                 self.assertEqual(u, {0: 'a', 1: 'c', 2: 'd'})
@@ -276,7 +276,7 @@ def test_mixed_or(self):
         self.assertIs(type(u), UserDictSubclass)
 
     def test_mixed_ior(self):
-        for t in UserDict, dict, types.MappingProxyType:
+        for t in UserDict, dict, frozendict, types.MappingProxyType:
             with self.subTest(t.__name__):
                 u = u2 = UserDict({0: 'a', 1: 'b'})
                 u |= t({1: 'c', 2: 'd'})
diff --git a/Objects/odictobject.c b/Objects/odictobject.c
index 25928028919c9c..21486806653ad0 100644
--- a/Objects/odictobject.c
+++ b/Objects/odictobject.c
@@ -906,7 +906,7 @@ odict_or(PyObject *left, PyObject *right)
         type = Py_TYPE(right);
         other = left;
     }
-    if (!PyDict_Check(other)) {
+    if (!PyAnyDict_Check(other)) {
         Py_RETURN_NOTIMPLEMENTED;
     }
     PyObject *new = PyObject_CallOneArg((PyObject*)type, left);
@@ -2271,7 +2271,7 @@ static int
 mutablemapping_update_arg(PyObject *self, PyObject *arg)
 {
     int res = 0;
-    if (PyDict_CheckExact(arg)) {
+    if (PyAnyDict_CheckExact(arg)) {
         PyObject *items = PyDict_Items(arg);
         if (items == NULL) {
             return -1;