diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index d8f1c3c..3b9be0e 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -33,6 +33,9 @@ vNext
 Fixes
 ~~~~~
 
+* **Postmark:** Fix spurious AnymailInvalidAddress in ``message.cc`` when
+  inbound message has no Cc recipients. (Thanks to `@Ecno92`_.)
+
 * **Postmark:** Workaround for handling inbound test webhooks.
   (`More info <https://github.com/anymail/django-anymail/issues/304>`__)
 
@@ -1428,6 +1431,7 @@ Features
 .. _@dgilmanAIDENTIFIED: https://github.com/dgilmanAIDENTIFIED
 .. _@dimitrisor: https://github.com/dimitrisor
 .. _@dominik-lekse: https://github.com/dominik-lekse
+.. _@Ecno92: https://github.com/Ecno92
 .. _@erikdrums: https://github.com/erikdrums
 .. _@ewingrj: https://github.com/ewingrj
 .. _@fdemmer: https://github.com/fdemmer
diff --git a/anymail/inbound.py b/anymail/inbound.py
index 21dbee0..1b3d35c 100644
--- a/anymail/inbound.py
+++ b/anymail/inbound.py
@@ -113,7 +113,10 @@ class AnymailInboundMessage(Message):
         """
         values = self.get_all(header)
         if values is not None:
-            values = parse_address_list(values)
+            if "".join(values).strip() == "":
+                values = None
+            else:
+                values = parse_address_list(values)
         return values or []
 
     def get_date_header(self, header):
diff --git a/tests/test_inbound.py b/tests/test_inbound.py
index b659bf2..224f827 100644
--- a/tests/test_inbound.py
+++ b/tests/test_inbound.py
@@ -307,6 +307,12 @@ class AnymailInboundMessageConveniencePropTests(SimpleTestCase):
         self.assertEqual(msg.to, [])
         self.assertEqual(msg.cc, [])
 
+        # Empty strings
+        msg = AnymailInboundMessage.construct(from_email="", to="", cc="")
+        self.assertIsNone(msg.from_email)
+        self.assertEqual(msg.to, [])
+        self.assertEqual(msg.cc, [])
+
     def test_body_props(self):
         msg = AnymailInboundMessage.construct(text="Test plaintext", html="Test HTML")
         self.assertEqual(msg.text, "Test plaintext")