diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2d03717..6889fdd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,7 @@
 
 ### Fixed
 
+- `MaildirConnection.fetch_message()` now marks messages as read after reading them (sets the `S` flag and moves the file from `new/` to `cur/`), unless `--test` is in effect. Previously, a message was processed but its on-disk maildir state was unchanged, so an MUA scanning the same maildir kept showing it as unread. Mirrors the existing `mark_read=not test` pattern used for `MSGraphConnection`.
 - `get_ip_address_info()` no longer caches weak-fallback attributions (no PTR + no ASN-domain map match → raw `as_name` used as `source_name`, `source_type` left null). `get_reverse_dns()` swallows every `DNSException` as `None`, so a transient PTR lookup failure (timeout, SERVFAIL, socket error) is indistinguishable from a genuine no-PTR case at that layer — caching the weak result would poison the 4-hour cache with a misattribution that persisted even after the PTR became resolvable again. PTR-backed matches and ASN-domain matches (both stable attributions) are still cached as before; only the specific `reverse_dns=None AND type=None AND name=as_name` state skips the cache write so the next lookup retries.
 
 ## 9.10.1
diff --git a/parsedmarc/__init__.py b/parsedmarc/__init__.py
index ce48c19..8b87b44 100644
--- a/parsedmarc/__init__.py
+++ b/parsedmarc/__init__.py
@@ -48,6 +48,7 @@ from parsedmarc.mail import (
     GmailConnection,
     IMAPConnection,
     MailboxConnection,
+    MaildirConnection,
     MSGraphConnection,
 )
 from parsedmarc.types import (
@@ -2042,6 +2043,9 @@ def get_dmarc_reports_from_mailbox(
         elif isinstance(connection, MSGraphConnection):
             message_id = str(msg_uid)
             msg_content = connection.fetch_message(message_id, mark_read=not test)
+        elif isinstance(connection, MaildirConnection):
+            message_id = str(msg_uid) if not isinstance(msg_uid, str) else msg_uid
+            msg_content = connection.fetch_message(message_id, mark_read=not test)
         else:
             message_id = str(msg_uid) if not isinstance(msg_uid, str) else msg_uid
             msg_content = connection.fetch_message(message_id)
diff --git a/parsedmarc/mail/maildir.py b/parsedmarc/mail/maildir.py
index 9f075e0..3e7a4f0 100644
--- a/parsedmarc/mail/maildir.py
+++ b/parsedmarc/mail/maildir.py
@@ -65,13 +65,18 @@ class MaildirConnection(MailboxConnection):
             self._active_folder = self._client
         return self._active_folder.keys()
 
-    def fetch_message(self, message_id: str) -> str:
+    def fetch_message(self, message_id: str, **kwargs) -> str:
         msg = self._active_folder.get(message_id)
-        if msg is not None:
-            msg = msg.as_string()
-            if msg is not None:
-                return msg
-        return ""
+        if msg is None:
+            return ""
+        msg_str = msg.as_string()
+        if kwargs.get("mark_read"):
+            # Maildir spec: a message is "read" once it has been moved out of
+            # new/ into cur/ with the "S" (Seen) flag set in its info field.
+            msg.set_subdir("cur")
+            msg.add_flag("S")
+            self._active_folder[message_id] = msg
+        return msg_str or ""
 
     def delete_message(self, message_id: str):
         self._active_folder.remove(message_id)