diff --git a/homeassistant/components/mqtt/__init__.py b/homeassistant/components/mqtt/__init__.py
index 7ff32a79142..6093be7d091 100644
--- a/homeassistant/components/mqtt/__init__.py
+++ b/homeassistant/components/mqtt/__init__.py
@@ -828,10 +828,10 @@ class MqttAvailability(Entity):
                  payload_not_available: Optional[str]) -> None:
         """Initialize the availability mixin."""
         self._availability_sub_state = None
+        self._available = False  # type: bool
 
         self._availability_topic = availability_topic
         self._availability_qos = qos
-        self._available = self._availability_topic is None  # type: bool
         self._payload_available = payload_available
         self._payload_not_available = payload_not_available
 
@@ -852,7 +852,6 @@ class MqttAvailability(Entity):
         """(Re)Setup."""
         self._availability_topic = config.get(CONF_AVAILABILITY_TOPIC)
         self._availability_qos = config.get(CONF_QOS)
-        self._available = self._availability_topic is None  # type: bool
         self._payload_available = config.get(CONF_PAYLOAD_AVAILABLE)
         self._payload_not_available = config.get(CONF_PAYLOAD_NOT_AVAILABLE)
 
@@ -887,7 +886,7 @@ class MqttAvailability(Entity):
     @property
     def available(self) -> bool:
         """Return if the device is available."""
-        return self._available
+        return self._availability_topic is None or self._available
 
 
 class MqttDiscoveryUpdate(Entity):