diff --git a/homeassistant/components/mqtt/client.py b/homeassistant/components/mqtt/client.py
index 7b43388fe933b1..b3fde3f8320260 100644
--- a/homeassistant/components/mqtt/client.py
+++ b/homeassistant/components/mqtt/client.py
@@ -452,7 +452,7 @@ def __init__(
         self._should_reconnect: bool = True
         self._available_future: asyncio.Future[bool] | None = None
 
-        self._max_qos: dict[str, int] = {}  # topic, max qos
+        self._max_qos: defaultdict[str, int] = defaultdict(int)  # topic, max qos
         self._pending_subscriptions: dict[str, int] = {}  # topic, qos
         self._unsubscribe_debouncer = EnsureJobAfterCooldown(
             UNSUBSCRIBE_COOLDOWN, self._async_perform_unsubscribes
@@ -820,8 +820,8 @@ def _async_queue_subscriptions(
         """Queue requested subscriptions."""
         for subscription in subscriptions:
             topic, qos = subscription
-            max_qos = max(qos, self._max_qos.setdefault(topic, qos))
-            self._max_qos[topic] = max_qos
+            if (max_qos := self._max_qos[topic]) < qos:
+                self._max_qos[topic] = (max_qos := qos)
             self._pending_subscriptions[topic] = max_qos
             # Cancel any pending unsubscribe since we are subscribing now
             if topic in self._pending_unsubscribes: