diff --git a/homeassistant/components/deconz/climate.py b/homeassistant/components/deconz/climate.py
index 98e3864e191..44111fbbb1e 100644
--- a/homeassistant/components/deconz/climate.py
+++ b/homeassistant/components/deconz/climate.py
@@ -26,7 +26,7 @@ from homeassistant.const import ATTR_TEMPERATURE, TEMP_CELSIUS
 from homeassistant.core import callback
 from homeassistant.helpers.dispatcher import async_dispatcher_connect
 
-from .const import ATTR_OFFSET, ATTR_VALVE, NEW_SENSOR
+from .const import ATTR_LOCKED, ATTR_OFFSET, ATTR_VALVE, NEW_SENSOR
 from .deconz_device import DeconzDevice
 from .gateway import get_gateway_from_config_entry
 
@@ -254,4 +254,7 @@ class DeconzThermostat(DeconzDevice, ClimateEntity):
         if self._device.valve is not None:
             attr[ATTR_VALVE] = self._device.valve
 
+        if self._device.locked is not None:
+            attr[ATTR_LOCKED] = self._device.locked
+
         return attr
diff --git a/homeassistant/components/deconz/const.py b/homeassistant/components/deconz/const.py
index cbad37b1b87..67effa4e81b 100644
--- a/homeassistant/components/deconz/const.py
+++ b/homeassistant/components/deconz/const.py
@@ -46,6 +46,7 @@ NEW_SCENE = "scenes"
 NEW_SENSOR = "sensors"
 
 ATTR_DARK = "dark"
+ATTR_LOCKED = "locked"
 ATTR_OFFSET = "offset"
 ATTR_ON = "on"
 ATTR_VALVE = "valve"
diff --git a/tests/components/deconz/test_climate.py b/tests/components/deconz/test_climate.py
index 0a37debade3..5577a2d0414 100644
--- a/tests/components/deconz/test_climate.py
+++ b/tests/components/deconz/test_climate.py
@@ -92,7 +92,7 @@ async def test_simple_climate_device(hass, aioclient_mock):
                 "battery": 59,
                 "displayflipped": None,
                 "heatsetpoint": 2100,
-                "locked": None,
+                "locked": True,
                 "mountingmode": None,
                 "offset": 0,
                 "on": True,
@@ -132,6 +132,7 @@ async def test_simple_climate_device(hass, aioclient_mock):
     ]
     assert climate_thermostat.attributes["current_temperature"] == 21.0
     assert climate_thermostat.attributes["temperature"] == 21.0
+    assert climate_thermostat.attributes["locked"] is True
     assert hass.states.get("sensor.thermostat_battery_level").state == "59"
 
     # Event signals thermostat configured off