diff --git a/homeassistant/components/mqtt/lock.py b/homeassistant/components/mqtt/lock.py
index e82498a9b12..5f1c169c349 100644
--- a/homeassistant/components/mqtt/lock.py
+++ b/homeassistant/components/mqtt/lock.py
@@ -12,7 +12,7 @@ from homeassistant.core import callback
 from homeassistant.components.lock import LockDevice
 from homeassistant.components.mqtt import (
     ATTR_DISCOVERY_HASH, CONF_COMMAND_TOPIC, CONF_QOS, CONF_RETAIN,
-    CONF_STATE_TOPIC, MqttAvailability, MqttDiscoveryUpdate,
+    CONF_STATE_TOPIC, MqttAttributes, MqttAvailability, MqttDiscoveryUpdate,
     MqttEntityDeviceInfo, subscription)
 from homeassistant.const import (
     CONF_DEVICE, CONF_NAME, CONF_OPTIMISTIC, CONF_VALUE_TEMPLATE)
@@ -44,7 +44,8 @@ PLATFORM_SCHEMA = mqtt.MQTT_RW_PLATFORM_SCHEMA.extend({
     vol.Optional(CONF_OPTIMISTIC, default=DEFAULT_OPTIMISTIC): cv.boolean,
     vol.Optional(CONF_UNIQUE_ID): cv.string,
     vol.Optional(CONF_DEVICE): mqtt.MQTT_ENTITY_DEVICE_INFO_SCHEMA,
-}).extend(mqtt.MQTT_AVAILABILITY_SCHEMA.schema)
+}).extend(mqtt.MQTT_AVAILABILITY_SCHEMA.schema).extend(
+    mqtt.MQTT_JSON_ATTRS_SCHEMA.schema)
 
 
 async def async_setup_platform(hass: HomeAssistantType, config: ConfigType,
@@ -78,8 +79,8 @@ async def _async_setup_entity(config, async_add_entities,
     async_add_entities([MqttLock(config, discovery_hash)])
 
 
-class MqttLock(MqttAvailability, MqttDiscoveryUpdate, MqttEntityDeviceInfo,
-               LockDevice):
+class MqttLock(MqttAttributes, MqttAvailability, MqttDiscoveryUpdate,
+               MqttEntityDeviceInfo, LockDevice):
     """Representation of a lock that can be toggled using MQTT."""
 
     def __init__(self, config, discovery_hash):
@@ -92,6 +93,7 @@ class MqttLock(MqttAvailability, MqttDiscoveryUpdate, MqttEntityDeviceInfo,
 
         device_config = config.get(CONF_DEVICE)
 
+        MqttAttributes.__init__(self, config)
         MqttAvailability.__init__(self, config)
         MqttDiscoveryUpdate.__init__(self, discovery_hash,
                                      self.discovery_update)
@@ -106,6 +108,7 @@ class MqttLock(MqttAvailability, MqttDiscoveryUpdate, MqttEntityDeviceInfo,
         """Handle updated discovery message."""
         config = PLATFORM_SCHEMA(discovery_payload)
         self._config = config
+        await self.attributes_discovery_update(config)
         await self.availability_discovery_update(config)
         await self._subscribe_topics()
         self.async_schedule_update_ha_state()
@@ -143,6 +146,7 @@ class MqttLock(MqttAvailability, MqttDiscoveryUpdate, MqttEntityDeviceInfo,
         """Unsubscribe when removed."""
         self._sub_state = await subscription.async_unsubscribe_topics(
             self.hass, self._sub_state)
+        await MqttAttributes.async_will_remove_from_hass(self)
         await MqttAvailability.async_will_remove_from_hass(self)
 
     @property
diff --git a/tests/components/mqtt/test_lock.py b/tests/components/mqtt/test_lock.py
index 83ae806d295..33802bc0795 100644
--- a/tests/components/mqtt/test_lock.py
+++ b/tests/components/mqtt/test_lock.py
@@ -139,6 +139,106 @@ async def test_custom_availability_payload(hass, mqtt_mock):
     assert state.state is STATE_UNAVAILABLE
 
 
+async def test_setting_attribute_via_mqtt_json_message(hass, mqtt_mock):
+    """Test the setting of attribute via MQTT with JSON payload."""
+    assert await async_setup_component(hass, lock.DOMAIN, {
+        lock.DOMAIN: {
+            'platform': 'mqtt',
+            'name': 'test',
+            'command_topic': 'test-topic',
+            'json_attributes_topic': 'attr-topic'
+        }
+    })
+
+    async_fire_mqtt_message(hass, 'attr-topic', '{ "val": "100" }')
+    await hass.async_block_till_done()
+    state = hass.states.get('lock.test')
+
+    assert '100' == state.attributes.get('val')
+
+
+async def test_update_with_json_attrs_not_dict(hass, mqtt_mock, caplog):
+    """Test attributes get extracted from a JSON result."""
+    assert await async_setup_component(hass, lock.DOMAIN, {
+        lock.DOMAIN: {
+            'platform': 'mqtt',
+            'name': 'test',
+            'command_topic': 'test-topic',
+            'json_attributes_topic': 'attr-topic'
+        }
+    })
+
+    async_fire_mqtt_message(hass, 'attr-topic', '[ "list", "of", "things"]')
+    await hass.async_block_till_done()
+    state = hass.states.get('lock.test')
+
+    assert state.attributes.get('val') is None
+    assert 'JSON result was not a dictionary' in caplog.text
+
+
+async def test_update_with_json_attrs_bad_JSON(hass, mqtt_mock, caplog):
+    """Test attributes get extracted from a JSON result."""
+    assert await async_setup_component(hass, lock.DOMAIN, {
+        lock.DOMAIN: {
+            'platform': 'mqtt',
+            'name': 'test',
+            'command_topic': 'test-topic',
+            'json_attributes_topic': 'attr-topic'
+        }
+    })
+
+    async_fire_mqtt_message(hass, 'attr-topic', 'This is not JSON')
+    await hass.async_block_till_done()
+
+    state = hass.states.get('lock.test')
+    assert state.attributes.get('val') is None
+    assert 'Erroneous JSON: This is not JSON' in caplog.text
+
+
+async def test_discovery_update_attr(hass, mqtt_mock, caplog):
+    """Test update of discovered MQTTAttributes."""
+    entry = MockConfigEntry(domain=mqtt.DOMAIN)
+    await async_start(hass, 'homeassistant', {}, entry)
+    data1 = (
+        '{ "name": "Beer",'
+        '  "command_topic": "test_topic",'
+        '  "json_attributes_topic": "attr-topic1" }'
+    )
+    data2 = (
+        '{ "name": "Beer",'
+        '  "command_topic": "test_topic",'
+        '  "json_attributes_topic": "attr-topic2" }'
+    )
+    async_fire_mqtt_message(hass, 'homeassistant/lock/bla/config',
+                            data1)
+    await hass.async_block_till_done()
+    async_fire_mqtt_message(hass, 'attr-topic1', '{ "val": "100" }')
+    await hass.async_block_till_done()
+    await hass.async_block_till_done()
+    state = hass.states.get('lock.beer')
+    assert '100' == state.attributes.get('val')
+
+    # Change json_attributes_topic
+    async_fire_mqtt_message(hass, 'homeassistant/lock/bla/config',
+                            data2)
+    await hass.async_block_till_done()
+    await hass.async_block_till_done()
+
+    # Verify we are no longer subscribing to the old topic
+    async_fire_mqtt_message(hass, 'attr-topic1', '{ "val": "50" }')
+    await hass.async_block_till_done()
+    await hass.async_block_till_done()
+    state = hass.states.get('lock.beer')
+    assert '100' == state.attributes.get('val')
+
+    # Verify we are subscribing to the new topic
+    async_fire_mqtt_message(hass, 'attr-topic2', '{ "val": "75" }')
+    await hass.async_block_till_done()
+    await hass.async_block_till_done()
+    state = hass.states.get('lock.beer')
+    assert '75' == state.attributes.get('val')
+
+
 async def test_unique_id(hass):
     """Test unique id option only creates one light per unique_id."""
     await async_mock_mqtt_component(hass)