diff --git a/nanobot/channels/signal.py b/nanobot/channels/signal.py
index 50d36c3af..3fd23c780 100644
--- a/nanobot/channels/signal.py
+++ b/nanobot/channels/signal.py
@@ -695,10 +695,7 @@ class SignalChannel(BaseChannel):
                 self.logger.debug(f"Ignoring DM from {sender_id} (DMs disabled)")
                 return
             if self.config.dm.policy == "allowlist":
-                allow_list = self.config.dm.allow_from
-                sender_str = str(sender_id)
-                parts = [sender_str] + (sender_str.split("|") if "|" in sender_str else [])
-                if not any(p for p in parts if p in allow_list):
+                if not self._sender_matches_allowlist(sender_id, self.config.dm.allow_from):
                     self.logger.debug(f"Ignoring DM from {sender_id} (policy: {self.config.dm.policy})")
                     return
 
@@ -864,6 +861,28 @@ class SignalChannel(BaseChannel):
             normalized.append(f"+{raw}")
         return list(dict.fromkeys(normalized))
 
+    @classmethod
+    def _sender_matches_allowlist(cls, sender_id: str, allow_list: list[str]) -> bool:
+        """Return True if any normalized variant of sender_id is on allow_list.
+
+        sender_id is the pipe-joined identifier string built by
+        _collect_sender_id_parts. Each part and each allow_list entry is run
+        through _normalize_signal_id so an allowlist entry like ``1234567890``
+        matches a sender ``+1234567890`` (and vice versa), and case-only
+        differences in UUIDs/ACIs match too.
+        """
+        if not allow_list:
+            return False
+        sender_variants: set[str] = set()
+        for part in str(sender_id).split("|"):
+            sender_variants.update(cls._normalize_signal_id(part))
+        if not sender_variants:
+            return False
+        allow_variants: set[str] = set()
+        for entry in allow_list:
+            allow_variants.update(cls._normalize_signal_id(entry))
+        return bool(sender_variants & allow_variants)
+
     def _remember_account_id_alias(self, value: str | None) -> None:
         """Remember known bot identifiers for mention matching."""
         if not value:
diff --git a/tests/channels/test_signal_channel.py b/tests/channels/test_signal_channel.py
index 27b8b1e91..d6308b803 100644
--- a/tests/channels/test_signal_channel.py
+++ b/tests/channels/test_signal_channel.py
@@ -510,6 +510,36 @@ class TestHandleDataMessageDM:
         await ch._handle_receive_notification(params)
         assert handled == []
 
+    @pytest.mark.asyncio
+    async def test_dm_allowlist_matches_without_plus_prefix(self):
+        """An allowlist entry without '+' must match a sender that carries '+'."""
+        ch, handled = self._make_dm_channel(policy="allowlist", allow_from=["19995550001"])
+        params = _dm_envelope(source_number="+19995550001")
+        await ch._handle_receive_notification(params)
+        assert len(handled) == 1
+
+    @pytest.mark.asyncio
+    async def test_dm_allowlist_matches_with_plus_prefix(self):
+        """An allowlist entry with '+' must match a sender without '+'."""
+        ch, handled = self._make_dm_channel(policy="allowlist", allow_from=["+19995550001"])
+        params = _dm_envelope(source_number="+19995550001", source_uuid=None)
+        # Replace envelope's sourceNumber with the non-prefixed form by editing
+        # the constructed dict directly so _collect_sender_id_parts sees it.
+        params["envelope"]["sourceNumber"] = "19995550001"
+        await ch._handle_receive_notification(params)
+        assert len(handled) == 1
+
+    @pytest.mark.asyncio
+    async def test_dm_allowlist_matches_uuid_case_insensitive(self):
+        """UUID matching must be case-insensitive."""
+        uuid = "ABCDEF12-3456-7890-ABCD-EF1234567890"
+        ch, handled = self._make_dm_channel(
+            policy="allowlist", allow_from=[uuid.lower()]
+        )
+        params = _dm_envelope(source_number="+19995550001", source_uuid=uuid)
+        await ch._handle_receive_notification(params)
+        assert len(handled) == 1
+
     @pytest.mark.asyncio
     async def test_dm_disabled_rejected(self):
         ch = _make_channel(dm_enabled=False)