diff --git a/zerver/lib/email_mirror.py b/zerver/lib/email_mirror.py
index 4f0271c12a..1f759d96c8 100644
--- a/zerver/lib/email_mirror.py
+++ b/zerver/lib/email_mirror.py
@@ -228,14 +228,9 @@ def filter_footer(text: str) -> str:
 
 def extract_and_upload_attachments(message: message.Message, realm: Realm) -> str:
     user_profile = get_system_bot(settings.EMAIL_GATEWAY_BOT)
+
     attachment_links = []
-
-    payload = message.get_payload()
-    if not isinstance(payload, list):
-        # This is not a multipart message, so it can't contain attachments.
-        return ""
-
-    for part in payload:
+    for part in message.walk():
         content_type = part.get_content_type()
         filename = part.get_filename()
         if filename:
@@ -251,7 +246,7 @@ def extract_and_upload_attachments(message: message.Message, realm: Realm) -> st
                 logger.warning("Payload is not bytes (invalid attachment %s in message from %s)." %
                                (filename, message.get("From")))
 
-    return "\n".join(attachment_links)
+    return '\n'.join(attachment_links)
 
 def decode_stream_email_address(email: str) -> Tuple[Stream, Dict[str, bool]]:
     token, options = decode_email_address(email)
diff --git a/zerver/tests/test_email_mirror.py b/zerver/tests/test_email_mirror.py
index a4c6cf40c3..35cfca5753 100644
--- a/zerver/tests/test_email_mirror.py
+++ b/zerver/tests/test_email_mirror.py
@@ -424,6 +424,44 @@ class TestEmailMirrorMessagesWithAttachments(ZulipTestCase):
         message = most_recent_message(user_profile)
         self.assertEqual(message.content, "Test body\n[image.png](https://test_url)")
 
+    def test_message_with_valid_nested_attachment(self) -> None:
+        user_profile = self.example_user('hamlet')
+        self.login(user_profile.email)
+        self.subscribe(user_profile, "Denmark")
+        stream = get_stream("Denmark", user_profile.realm)
+        stream_to_address = encode_email_address(stream)
+
+        incoming_valid_message = MIMEMultipart()
+        text_msg = MIMEText("Test body")
+        incoming_valid_message.attach(text_msg)
+
+        nested_multipart = MIMEMultipart()
+        nested_text_message = MIMEText("Nested text that should get skipped.")
+        nested_multipart.attach(nested_text_message)
+        with open(os.path.join(settings.DEPLOY_ROOT, "static/images/default-avatar.png"), 'rb') as f:
+            image_bytes = f.read()
+
+        attachment_msg = MIMEImage(image_bytes)
+        attachment_msg.add_header('Content-Disposition', 'attachment', filename="image.png")
+        nested_multipart.attach(attachment_msg)
+        incoming_valid_message.attach(nested_multipart)
+
+        incoming_valid_message['Subject'] = 'Subject'
+        incoming_valid_message['From'] = self.example_email('hamlet')
+        incoming_valid_message['To'] = stream_to_address
+        incoming_valid_message['Reply-to'] = self.example_email('othello')
+
+        with mock.patch('zerver.lib.email_mirror.upload_message_file',
+                        return_value='https://test_url') as upload_message_file:
+            process_message(incoming_valid_message)
+            upload_message_file.assert_called_with('image.png', len(image_bytes),
+                                                   'image/png', image_bytes,
+                                                   get_system_bot(settings.EMAIL_GATEWAY_BOT),
+                                                   target_realm=user_profile.realm)
+
+        message = most_recent_message(user_profile)
+        self.assertEqual(message.content, "Test body\n[image.png](https://test_url)")
+
     def test_message_with_invalid_attachment(self) -> None:
         user_profile = self.example_user('hamlet')
         self.login(user_profile.email)