diff --git a/django/test/testcases.py b/django/test/testcases.py
index 41d01b89b4..7d12594177 100644
--- a/django/test/testcases.py
+++ b/django/test/testcases.py
@@ -1139,23 +1139,7 @@ class TestData:
         if instance is None:
             return self.data
         memo = self.get_memo(instance)
-        try:
-            data = deepcopy(self.data, memo)
-        except TypeError:
-            # RemovedInDjango41Warning.
-            msg = (
-                "Assigning objects which don't support copy.deepcopy() during "
-                "setUpTestData() is deprecated. Either assign the %s "
-                "attribute during setUpClass() or setUp(), or add support for "
-                "deepcopy() to %s.%s.%s."
-            ) % (
-                self.name,
-                owner.__module__,
-                owner.__qualname__,
-                self.name,
-            )
-            warnings.warn(msg, category=RemovedInDjango41Warning, stacklevel=2)
-            data = self.data
+        data = deepcopy(self.data, memo)
         setattr(instance, self.name, data)
         return data
 
diff --git a/docs/releases/4.1.txt b/docs/releases/4.1.txt
index 8a65b94581..bf3f3a848f 100644
--- a/docs/releases/4.1.txt
+++ b/docs/releases/4.1.txt
@@ -246,4 +246,6 @@ in Django 4.1.
 See :ref:`deprecated-features-3.2` for details on these changes, including how
 to remove usage of these features.
 
-* ...
+* Support for assigning objects which don't support creating deep copies with
+  ``copy.deepcopy()`` to class attributes in ``TestCase.setUpTestData()`` is
+  removed.
diff --git a/tests/test_utils/test_testcase.py b/tests/test_utils/test_testcase.py
index 9b11168b13..1261006092 100644
--- a/tests/test_utils/test_testcase.py
+++ b/tests/test_utils/test_testcase.py
@@ -1,9 +1,8 @@
 from functools import wraps
 
 from django.db import IntegrityError, connections, transaction
-from django.test import TestCase, ignore_warnings, skipUnlessDBFeature
+from django.test import TestCase, skipUnlessDBFeature
 from django.test.testcases import TestData
-from django.utils.deprecation import RemovedInDjango41Warning
 
 from .models import Car, Person, PossessedCar
 
@@ -54,11 +53,6 @@ class TestTestCase(TestCase):
             self.reset_sequences = old_reset_sequences
 
 
-class NonDeepCopyAble:
-    def __deepcopy__(self, memo):
-        raise TypeError
-
-
 def assert_no_queries(test):
     @wraps(test)
     def inner(self):
@@ -79,7 +73,6 @@ class TestDataTests(TestCase):
             car=cls.car,
             belongs_to=cls.jim_douglas,
         )
-        cls.non_deepcopy_able = NonDeepCopyAble()
 
     @assert_no_queries
     def test_class_attribute_equality(self):
@@ -104,21 +97,6 @@ class TestDataTests(TestCase):
         self.assertIs(self.herbie.car, self.car)
         self.assertIs(self.herbie.belongs_to, self.jim_douglas)
 
-    @ignore_warnings(category=RemovedInDjango41Warning)
-    def test_undeepcopyable(self):
-        self.assertIs(self.non_deepcopy_able, self.__class__.non_deepcopy_able)
-
-    def test_undeepcopyable_warning(self):
-        msg = (
-            "Assigning objects which don't support copy.deepcopy() during "
-            "setUpTestData() is deprecated. Either assign the "
-            "non_deepcopy_able attribute during setUpClass() or setUp(), or "
-            "add support for deepcopy() to "
-            "test_utils.test_testcase.TestDataTests.non_deepcopy_able."
-        )
-        with self.assertRaisesMessage(RemovedInDjango41Warning, msg):
-            self.non_deepcopy_able
-
     def test_repr(self):
         self.assertEqual(
             repr(TestData('attr', 'value')),