diff --git a/Lib/ctypes/test/test_bitfields.py b/Lib/ctypes/test/test_bitfields.py
index 992b8c4da3a..54023428dd7 100644
--- a/Lib/ctypes/test/test_bitfields.py
+++ b/Lib/ctypes/test/test_bitfields.py
@@ -233,6 +233,78 @@ class BitFieldTest(unittest.TestCase):
         else:
             self.assertEqual(sizeof(X), sizeof(c_int) * 2)
 
+    @unittest.skipIf(os.name == 'nt', reason='Posix only')
+    def test_packed_posix(self):
+        test_cases = {
+            (
+                ("a", c_uint8, 4),
+                ("b", c_uint8, 4),
+            ): 1,
+            (
+                ("a", c_uint8, 1),
+                ("b", c_uint16, 1),
+                ("c", c_uint32, 1),
+                ("d", c_uint64, 1),
+            ): 1,
+            (
+                ("a", c_uint8, 8),
+                ("b", c_uint16, 1),
+                ("c", c_uint32, 1),
+                ("d", c_uint64, 1),
+            ): 2,
+            (
+                ("a", c_uint32, 9),
+                ("b", c_uint16, 10),
+                ("c", c_uint32, 25),
+                ("d", c_uint64, 1),
+            ): 6,
+            (
+                ("a", c_uint32, 9),
+                ("b", c_uint16, 10),
+                ("c", c_uint32, 25),
+                ("d", c_uint64, 5),
+            ): 7,
+            (
+                ("a", c_uint16),
+                ("b", c_uint16, 9),
+                ("c", c_uint16, 1),
+                ("d", c_uint16, 1),
+                ("e", c_uint16, 1),
+                ("f", c_uint16, 1),
+                ("g", c_uint16, 3),
+                ("h", c_uint32, 10),
+                ("i", c_uint32, 20),
+                ("j", c_uint32, 2),
+            ): 8,
+            (
+                ("a", c_uint16, 9),
+                ("b", c_uint16, 10),
+                ("d", c_uint16),
+                ("c", c_uint8, 8),
+            ): 6,
+            (
+                ("a", c_uint32, 9),
+                ("b", c_uint32),
+                ("c", c_uint32, 8),
+            ): 7,
+        }
+
+        for fields, size in test_cases.items():
+            with self.subTest(fields=fields):
+                class X(Structure):
+                    _pack_ = 1
+                    _fields_ = list(fields)
+                self.assertEqual(sizeof(X), size)
+
+    def test_packed_8(self):
+        class X(Structure):
+            _pack_ = 1
+            _fields_ = [("a", c_uint32, 9),
+                        ("b", c_uint32),
+                        ("c", c_uint32, 8)]
+        if os.name != "nt":
+            self.assertEqual(sizeof(X), 7)
+
     def test_anon_bitfields(self):
         # anonymous bit-fields gave a strange error message
         class X(Structure):