diff --git a/homeassistant/components/energy/sensor.py b/homeassistant/components/energy/sensor.py
index 5ad4c74a6cf..6f16d2dc831 100644
--- a/homeassistant/components/energy/sensor.py
+++ b/homeassistant/components/energy/sensor.py
@@ -43,6 +43,7 @@ SUPPORTED_STATE_CLASSES = {
 VALID_ENERGY_UNITS: set[str] = {
     UnitOfEnergy.GIGA_JOULE,
     UnitOfEnergy.KILO_WATT_HOUR,
+    UnitOfEnergy.MEGA_JOULE,
     UnitOfEnergy.MEGA_WATT_HOUR,
     UnitOfEnergy.WATT_HOUR,
 }
diff --git a/homeassistant/components/energy/validate.py b/homeassistant/components/energy/validate.py
index f8f276f6438..a2c3ad094da 100644
--- a/homeassistant/components/energy/validate.py
+++ b/homeassistant/components/energy/validate.py
@@ -23,6 +23,7 @@ ENERGY_USAGE_UNITS = {
     sensor.SensorDeviceClass.ENERGY: (
         UnitOfEnergy.GIGA_JOULE,
         UnitOfEnergy.KILO_WATT_HOUR,
+        UnitOfEnergy.MEGA_JOULE,
         UnitOfEnergy.MEGA_WATT_HOUR,
         UnitOfEnergy.WATT_HOUR,
     )
@@ -40,6 +41,7 @@ GAS_USAGE_UNITS = {
     sensor.SensorDeviceClass.ENERGY: (
         UnitOfEnergy.GIGA_JOULE,
         UnitOfEnergy.KILO_WATT_HOUR,
+        UnitOfEnergy.MEGA_JOULE,
         UnitOfEnergy.MEGA_WATT_HOUR,
         UnitOfEnergy.WATT_HOUR,
     ),
diff --git a/homeassistant/components/number/const.py b/homeassistant/components/number/const.py
index c10d677b773..b3f31ac23fe 100644
--- a/homeassistant/components/number/const.py
+++ b/homeassistant/components/number/const.py
@@ -122,7 +122,7 @@ class NumberDeviceClass(StrEnum):
     ENERGY = "energy"
     """Energy.
 
-    Unit of measurement: `Wh`, `kWh`, `MWh`, `GJ`
+    Unit of measurement: `Wh`, `kWh`, `MWh`, `MJ`, `GJ`
     """
 
     FREQUENCY = "frequency"
diff --git a/homeassistant/components/sensor/const.py b/homeassistant/components/sensor/const.py
index 66d231bea24..93fccbab124 100644
--- a/homeassistant/components/sensor/const.py
+++ b/homeassistant/components/sensor/const.py
@@ -159,7 +159,7 @@ class SensorDeviceClass(StrEnum):
     ENERGY = "energy"
     """Energy.
 
-    Unit of measurement: `Wh`, `kWh`, `MWh`, `GJ`
+    Unit of measurement: `Wh`, `kWh`, `MWh`, `MJ`, `GJ`
     """
 
     FREQUENCY = "frequency"
diff --git a/homeassistant/const.py b/homeassistant/const.py
index 4be0be42f76..44cec9fb861 100644
--- a/homeassistant/const.py
+++ b/homeassistant/const.py
@@ -517,6 +517,7 @@ class UnitOfEnergy(StrEnum):
 
     GIGA_JOULE = "GJ"
     KILO_WATT_HOUR = "kWh"
+    MEGA_JOULE = "MJ"
     MEGA_WATT_HOUR = "MWh"
     WATT_HOUR = "Wh"
 
diff --git a/homeassistant/util/unit_conversion.py b/homeassistant/util/unit_conversion.py
index 930e5a71e42..0fde15acd71 100644
--- a/homeassistant/util/unit_conversion.py
+++ b/homeassistant/util/unit_conversion.py
@@ -176,12 +176,14 @@ class EnergyConverter(BaseUnitConverter):
         UnitOfEnergy.WATT_HOUR: 1 * 1000,
         UnitOfEnergy.KILO_WATT_HOUR: 1,
         UnitOfEnergy.MEGA_WATT_HOUR: 1 / 1000,
+        UnitOfEnergy.MEGA_JOULE: 3.6,
         UnitOfEnergy.GIGA_JOULE: 3.6 / 1000,
     }
     VALID_UNITS = {
         UnitOfEnergy.WATT_HOUR,
         UnitOfEnergy.KILO_WATT_HOUR,
         UnitOfEnergy.MEGA_WATT_HOUR,
+        UnitOfEnergy.MEGA_JOULE,
         UnitOfEnergy.GIGA_JOULE,
     }
 
diff --git a/tests/components/energy/test_validate.py b/tests/components/energy/test_validate.py
index 4aa852e69e0..924a63dc12c 100644
--- a/tests/components/energy/test_validate.py
+++ b/tests/components/energy/test_validate.py
@@ -220,7 +220,9 @@ async def test_validation_device_consumption_entity_unexpected_unit(
                 {
                     "type": "entity_unexpected_unit_energy",
                     "affected_entities": {("sensor.unexpected_unit", "beers")},
-                    "translation_placeholders": {"energy_units": "GJ, kWh, MWh, Wh"},
+                    "translation_placeholders": {
+                        "energy_units": "GJ, kWh, MJ, MWh, Wh"
+                    },
                 }
             ]
         ],
@@ -306,7 +308,9 @@ async def test_validation_solar(hass, mock_energy_manager, mock_get_metadata):
                 {
                     "type": "entity_unexpected_unit_energy",
                     "affected_entities": {("sensor.solar_production", "beers")},
-                    "translation_placeholders": {"energy_units": "GJ, kWh, MWh, Wh"},
+                    "translation_placeholders": {
+                        "energy_units": "GJ, kWh, MJ, MWh, Wh"
+                    },
                 }
             ]
         ],
@@ -355,7 +359,9 @@ async def test_validation_battery(hass, mock_energy_manager, mock_get_metadata):
                         ("sensor.battery_import", "beers"),
                         ("sensor.battery_export", "beers"),
                     },
-                    "translation_placeholders": {"energy_units": "GJ, kWh, MWh, Wh"},
+                    "translation_placeholders": {
+                        "energy_units": "GJ, kWh, MJ, MWh, Wh"
+                    },
                 },
             ]
         ],
@@ -424,7 +430,9 @@ async def test_validation_grid(
                         ("sensor.grid_consumption_1", "beers"),
                         ("sensor.grid_production_1", "beers"),
                     },
-                    "translation_placeholders": {"energy_units": "GJ, kWh, MWh, Wh"},
+                    "translation_placeholders": {
+                        "energy_units": "GJ, kWh, MJ, MWh, Wh"
+                    },
                 },
                 {
                     "type": "statistics_not_defined",
@@ -511,7 +519,9 @@ async def test_validation_grid_external_cost_compensation(
                         ("sensor.grid_consumption_1", "beers"),
                         ("sensor.grid_production_1", "beers"),
                     },
-                    "translation_placeholders": {"energy_units": "GJ, kWh, MWh, Wh"},
+                    "translation_placeholders": {
+                        "energy_units": "GJ, kWh, MJ, MWh, Wh"
+                    },
                 },
                 {
                     "type": "statistics_not_defined",
@@ -678,7 +688,7 @@ async def test_validation_grid_auto_cost_entity_errors(
                 "type": "entity_unexpected_unit_energy_price",
                 "affected_entities": {("sensor.grid_price_1", "$/Ws")},
                 "translation_placeholders": {
-                    "price_units": "EUR/GJ, EUR/kWh, EUR/MWh, EUR/Wh"
+                    "price_units": "EUR/GJ, EUR/kWh, EUR/MJ, EUR/MWh, EUR/Wh"
                 },
             },
         ),
@@ -822,7 +832,7 @@ async def test_validation_gas(
                     "type": "entity_unexpected_unit_gas",
                     "affected_entities": {("sensor.gas_consumption_1", "beers")},
                     "translation_placeholders": {
-                        "energy_units": "GJ, kWh, MWh, Wh",
+                        "energy_units": "GJ, kWh, MJ, MWh, Wh",
                         "gas_units": "CCF, ft³, m³",
                     },
                 },
@@ -852,7 +862,7 @@ async def test_validation_gas(
                     "affected_entities": {("sensor.gas_price_2", "EUR/invalid")},
                     "translation_placeholders": {
                         "price_units": (
-                            "EUR/GJ, EUR/kWh, EUR/MWh, EUR/Wh, EUR/CCF, EUR/ft³, EUR/m³"
+                            "EUR/GJ, EUR/kWh, EUR/MJ, EUR/MWh, EUR/Wh, EUR/CCF, EUR/ft³, EUR/m³"
                         )
                     },
                 },
diff --git a/tests/util/test_unit_conversion.py b/tests/util/test_unit_conversion.py
index b18813a4079..648db8420d3 100644
--- a/tests/util/test_unit_conversion.py
+++ b/tests/util/test_unit_conversion.py
@@ -208,6 +208,8 @@ _CONVERTED_VALUE: dict[
         (10, UnitOfEnergy.MEGA_WATT_HOUR, 10000, UnitOfEnergy.KILO_WATT_HOUR),
         (10, UnitOfEnergy.GIGA_JOULE, 10000 / 3.6, UnitOfEnergy.KILO_WATT_HOUR),
         (10, UnitOfEnergy.GIGA_JOULE, 10 / 3.6, UnitOfEnergy.MEGA_WATT_HOUR),
+        (10, UnitOfEnergy.MEGA_JOULE, 10 / 3.6, UnitOfEnergy.KILO_WATT_HOUR),
+        (10, UnitOfEnergy.MEGA_JOULE, 0.010 / 3.6, UnitOfEnergy.MEGA_WATT_HOUR),
     ],
     InformationConverter: [
         (8e3, UnitOfInformation.BITS, 8, UnitOfInformation.KILOBITS),