diff --git a/homeassistant/components/modbus/light.py b/homeassistant/components/modbus/light.py
index 2313dd9bacb..451c13ea3ff 100644
--- a/homeassistant/components/modbus/light.py
+++ b/homeassistant/components/modbus/light.py
@@ -3,7 +3,7 @@ from __future__ import annotations
 
 from typing import Any
 
-from homeassistant.components.light import LightEntity
+from homeassistant.components.light import COLOR_MODE_ONOFF, LightEntity
 from homeassistant.const import CONF_LIGHTS, CONF_NAME
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
@@ -36,6 +36,9 @@ async def async_setup_platform(
 class ModbusLight(BaseSwitch, LightEntity):
     """Class representing a Modbus light."""
 
+    _attr_color_mode = COLOR_MODE_ONOFF
+    _attr_supported_color_modes = {COLOR_MODE_ONOFF}
+
     async def async_turn_on(self, **kwargs: Any) -> None:
         """Set light on."""
         await self.async_turn(self.command_on)