diff --git a/homeassistant/components/modbus/sensor.py b/homeassistant/components/modbus/sensor.py
index d7a6b4cca0f..52aa37535d6 100644
--- a/homeassistant/components/modbus/sensor.py
+++ b/homeassistant/components/modbus/sensor.py
@@ -168,6 +168,7 @@ class SlaveSensor(
             self._attr_unique_id = f"{self._attr_unique_id}_{idx}"
         self._attr_native_unit_of_measurement = entry.get(CONF_UNIT_OF_MEASUREMENT)
         self._attr_state_class = entry.get(CONF_STATE_CLASS)
+        self._attr_device_class = entry.get(CONF_DEVICE_CLASS)
         self._attr_available = False
         super().__init__(coordinator)