diff --git a/homeassistant/components/energy/sensor.py b/homeassistant/components/energy/sensor.py
index 1d919e07737..207003303e2 100644
--- a/homeassistant/components/energy/sensor.py
+++ b/homeassistant/components/energy/sensor.py
@@ -20,6 +20,7 @@ from homeassistant.components.sensor.recorder import reset_detected
 from homeassistant.const import (
     ATTR_UNIT_OF_MEASUREMENT,
     ENERGY_KILO_WATT_HOUR,
+    ENERGY_MEGA_WATT_HOUR,
     ENERGY_WATT_HOUR,
     VOLUME_CUBIC_METERS,
 )
@@ -43,6 +44,8 @@ SUPPORTED_STATE_CLASSES = [
     STATE_CLASS_TOTAL,
     STATE_CLASS_TOTAL_INCREASING,
 ]
+VALID_ENERGY_UNITS = [ENERGY_WATT_HOUR, ENERGY_KILO_WATT_HOUR, ENERGY_MEGA_WATT_HOUR]
+VALID_ENERGY_UNITS_GAS = [VOLUME_CUBIC_METERS] + VALID_ENERGY_UNITS
 _LOGGER = logging.getLogger(__name__)
 
 
@@ -289,14 +292,16 @@ class EnergyCostSensor(SensorEntity):
             except ValueError:
                 return
 
-            if (
-                self._adapter.source_type == "grid"
-                and energy_price_state.attributes.get(
-                    ATTR_UNIT_OF_MEASUREMENT, ""
-                ).endswith(f"/{ENERGY_WATT_HOUR}")
+            if energy_price_state.attributes.get(ATTR_UNIT_OF_MEASUREMENT, "").endswith(
+                f"/{ENERGY_WATT_HOUR}"
             ):
                 energy_price *= 1000.0
 
+            if energy_price_state.attributes.get(ATTR_UNIT_OF_MEASUREMENT, "").endswith(
+                f"/{ENERGY_MEGA_WATT_HOUR}"
+            ):
+                energy_price /= 1000.0
+
         else:
             energy_price_state = None
             energy_price = cast(float, self._config["number_energy_price"])
@@ -309,15 +314,18 @@ class EnergyCostSensor(SensorEntity):
         energy_unit = energy_state.attributes.get(ATTR_UNIT_OF_MEASUREMENT)
 
         if self._adapter.source_type == "grid":
-            if energy_unit == ENERGY_WATT_HOUR:
-                energy_price /= 1000
-            elif energy_unit != ENERGY_KILO_WATT_HOUR:
+            if energy_unit not in VALID_ENERGY_UNITS:
                 energy_unit = None
 
         elif self._adapter.source_type == "gas":
-            if energy_unit != VOLUME_CUBIC_METERS:
+            if energy_unit not in VALID_ENERGY_UNITS_GAS:
                 energy_unit = None
 
+        if energy_unit == ENERGY_WATT_HOUR:
+            energy_price /= 1000
+        elif energy_unit == ENERGY_MEGA_WATT_HOUR:
+            energy_unit *= 1000
+
         if energy_unit is None:
             if not self._wrong_unit_reported:
                 self._wrong_unit_reported = True
diff --git a/tests/components/energy/test_sensor.py b/tests/components/energy/test_sensor.py
index 3d0eb5b1318..133cde814aa 100644
--- a/tests/components/energy/test_sensor.py
+++ b/tests/components/energy/test_sensor.py
@@ -19,6 +19,7 @@ from homeassistant.const import (
     ATTR_UNIT_OF_MEASUREMENT,
     DEVICE_CLASS_MONETARY,
     ENERGY_KILO_WATT_HOUR,
+    ENERGY_MEGA_WATT_HOUR,
     ENERGY_WATT_HOUR,
     STATE_UNKNOWN,
     VOLUME_CUBIC_METERS,
@@ -718,6 +719,62 @@ async def test_cost_sensor_handle_wh(hass, hass_storage) -> None:
     assert state.state == "5.0"
 
 
+async def test_cost_sensor_handle_mwh(hass, hass_storage) -> None:
+    """Test energy cost price from sensor entity."""
+    energy_attributes = {
+        ATTR_UNIT_OF_MEASUREMENT: ENERGY_MEGA_WATT_HOUR,
+        ATTR_STATE_CLASS: STATE_CLASS_TOTAL_INCREASING,
+    }
+    energy_data = data.EnergyManager.default_preferences()
+    energy_data["energy_sources"].append(
+        {
+            "type": "grid",
+            "flow_from": [
+                {
+                    "stat_energy_from": "sensor.energy_consumption",
+                    "entity_energy_from": "sensor.energy_consumption",
+                    "stat_cost": None,
+                    "entity_energy_price": None,
+                    "number_energy_price": 2.0,
+                }
+            ],
+            "flow_to": [],
+            "cost_adjustment_day": 0,
+        }
+    )
+
+    hass_storage[data.STORAGE_KEY] = {
+        "version": 1,
+        "data": energy_data,
+    }
+
+    now = dt_util.utcnow()
+
+    # Initial state: 0.5MWh
+    hass.states.async_set(
+        "sensor.energy_consumption",
+        0.5,
+        energy_attributes,
+    )
+
+    with patch("homeassistant.util.dt.utcnow", return_value=now):
+        await setup_integration(hass)
+
+    state = hass.states.get("sensor.energy_consumption_cost")
+    assert state.state == "0.0"
+
+    # Energy use bumped by 1 MWh
+    hass.states.async_set(
+        "sensor.energy_consumption",
+        1.5,
+        energy_attributes,
+    )
+    await hass.async_block_till_done()
+
+    state = hass.states.get("sensor.energy_consumption_cost")
+    assert state.state == "2.0"
+
+
 async def test_cost_sensor_handle_gas(hass, hass_storage) -> None:
     """Test gas cost price from sensor entity."""
     energy_attributes = {
@@ -767,6 +824,55 @@ async def test_cost_sensor_handle_gas(hass, hass_storage) -> None:
     assert state.state == "50.0"
 
 
+async def test_cost_sensor_handle_gas_kwh(hass, hass_storage) -> None:
+    """Test gas cost price from sensor entity."""
+    energy_attributes = {
+        ATTR_UNIT_OF_MEASUREMENT: ENERGY_KILO_WATT_HOUR,
+        ATTR_STATE_CLASS: STATE_CLASS_TOTAL_INCREASING,
+    }
+    energy_data = data.EnergyManager.default_preferences()
+    energy_data["energy_sources"].append(
+        {
+            "type": "gas",
+            "stat_energy_from": "sensor.gas_consumption",
+            "entity_energy_from": "sensor.gas_consumption",
+            "stat_cost": None,
+            "entity_energy_price": None,
+            "number_energy_price": 0.5,
+        }
+    )
+
+    hass_storage[data.STORAGE_KEY] = {
+        "version": 1,
+        "data": energy_data,
+    }
+
+    now = dt_util.utcnow()
+
+    hass.states.async_set(
+        "sensor.gas_consumption",
+        100,
+        energy_attributes,
+    )
+
+    with patch("homeassistant.util.dt.utcnow", return_value=now):
+        await setup_integration(hass)
+
+    state = hass.states.get("sensor.gas_consumption_cost")
+    assert state.state == "0.0"
+
+    # gas use bumped to 10 kWh
+    hass.states.async_set(
+        "sensor.gas_consumption",
+        200,
+        energy_attributes,
+    )
+    await hass.async_block_till_done()
+
+    state = hass.states.get("sensor.gas_consumption_cost")
+    assert state.state == "50.0"
+
+
 @pytest.mark.parametrize("state_class", [None])
 async def test_cost_sensor_wrong_state_class(
     hass, hass_storage, caplog, state_class