diff --git a/web-greeter/bridge/Greeter.py b/web-greeter/bridge/Greeter.py
index bc53781..32e2d5d 100644
--- a/web-greeter/bridge/Greeter.py
+++ b/web-greeter/bridge/Greeter.py
@@ -181,6 +181,10 @@ class Greeter(BridgeObject):
     def brightness(self):
         return getBrightness(self)
 
+    @brightness.setter
+    def brightness(self, quantity):
+        return changeBrightness(self, "-set", quantity)
+
     @bridge.prop(bool, notify=noop_signal)
     def can_hibernate(self):
         return LightDM.get_can_hibernate()