diff --git a/homeassistant/components/mysensors/light.py b/homeassistant/components/mysensors/light.py
index 81089f052b6..b08d94cebb0 100644
--- a/homeassistant/components/mysensors/light.py
+++ b/homeassistant/components/mysensors/light.py
@@ -132,7 +132,6 @@ class MySensorsLight(mysensors.device.MySensorsEntity, LightEntity):
     def _turn_on_rgb_and_w(self, hex_template: str, **kwargs: Any) -> None:
         """Turn on RGB or RGBW child device."""
         assert self._hs
-        assert self._white is not None
         rgb = list(color_util.color_hs_to_RGB(*self._hs))
         white = self._white
         hex_color = self._values.get(self.value_type)
@@ -151,8 +150,10 @@ class MySensorsLight(mysensors.device.MySensorsEntity, LightEntity):
         if hex_template == "%02x%02x%02x%02x":
             if new_white is not None:
                 rgb.append(new_white)
-            else:
+            elif white is not None:
                 rgb.append(white)
+            else:
+                rgb.append(0)
         hex_color = hex_template % tuple(rgb)
         if len(rgb) > 3:
             white = rgb.pop()