diff --git a/homeassistant/components/heos/const.py b/homeassistant/components/heos/const.py
index 7f03fa11e79..0203def3885 100644
--- a/homeassistant/components/heos/const.py
+++ b/homeassistant/components/heos/const.py
@@ -3,5 +3,6 @@
 ATTR_PASSWORD = "password"
 ATTR_USERNAME = "username"
 DOMAIN = "heos"
+SERVICE_GROUP_VOLUME_SET = "group_volume_set"
 SERVICE_SIGN_IN = "sign_in"
 SERVICE_SIGN_OUT = "sign_out"
diff --git a/homeassistant/components/heos/icons.json b/homeassistant/components/heos/icons.json
index 23c2c8faeaf..a634701037c 100644
--- a/homeassistant/components/heos/icons.json
+++ b/homeassistant/components/heos/icons.json
@@ -1,5 +1,8 @@
 {
   "services": {
+    "group_volume_set": {
+      "service": "mdi:volume-medium"
+    },
     "sign_in": {
       "service": "mdi:login"
     },
diff --git a/homeassistant/components/heos/media_player.py b/homeassistant/components/heos/media_player.py
index b9aa05810e5..a649740a933 100644
--- a/homeassistant/components/heos/media_player.py
+++ b/homeassistant/components/heos/media_player.py
@@ -17,10 +17,12 @@ from pyheos import (
     RepeatType,
     const as heos_const,
 )
+import voluptuous as vol
 
 from homeassistant.components import media_source
 from homeassistant.components.media_player import (
     ATTR_MEDIA_ENQUEUE,
+    ATTR_MEDIA_VOLUME_LEVEL,
     BrowseMedia,
     MediaPlayerEnqueue,
     MediaPlayerEntity,
@@ -33,13 +35,17 @@ from homeassistant.components.media_player import (
 from homeassistant.const import Platform
 from homeassistant.core import HomeAssistant, callback
 from homeassistant.exceptions import HomeAssistantError, ServiceValidationError
-from homeassistant.helpers import entity_registry as er
+from homeassistant.helpers import (
+    config_validation as cv,
+    entity_platform,
+    entity_registry as er,
+)
 from homeassistant.helpers.device_registry import DeviceInfo
 from homeassistant.helpers.entity_platform import AddConfigEntryEntitiesCallback
 from homeassistant.helpers.update_coordinator import CoordinatorEntity
 from homeassistant.util.dt import utcnow
 
-from .const import DOMAIN as HEOS_DOMAIN
+from .const import DOMAIN as HEOS_DOMAIN, SERVICE_GROUP_VOLUME_SET
 from .coordinator import HeosConfigEntry, HeosCoordinator
 
 PARALLEL_UPDATES = 0
@@ -93,6 +99,13 @@ async def async_setup_entry(
     async_add_entities: AddConfigEntryEntitiesCallback,
 ) -> None:
     """Add media players for a config entry."""
+    # Register custom entity services
+    platform = entity_platform.async_get_current_platform()
+    platform.async_register_entity_service(
+        SERVICE_GROUP_VOLUME_SET,
+        {vol.Required(ATTR_MEDIA_VOLUME_LEVEL): cv.small_float},
+        "async_set_group_volume_level",
+    )
 
     def add_entities_callback(players: Sequence[HeosPlayer]) -> None:
         """Add entities for each player."""
@@ -346,6 +359,19 @@ class HeosMediaPlayer(CoordinatorEntity[HeosCoordinator], MediaPlayerEntity):
         """Set volume level, range 0..1."""
         await self._player.set_volume(int(volume * 100))
 
+    @catch_action_error("set group volume level")
+    async def async_set_group_volume_level(self, volume_level: float) -> None:
+        """Set group volume level."""
+        if self._player.group_id is None:
+            raise ServiceValidationError(
+                translation_domain=HEOS_DOMAIN,
+                translation_key="entity_not_grouped",
+                translation_placeholders={"entity_id": self.entity_id},
+            )
+        await self.coordinator.heos.set_group_volume(
+            self._player.group_id, int(volume_level * 100)
+        )
+
     @catch_action_error("join players")
     async def async_join_players(self, group_members: list[str]) -> None:
         """Join `group_members` as a player group with the current player."""
diff --git a/homeassistant/components/heos/services.yaml b/homeassistant/components/heos/services.yaml
index 8dc222d65ba..948aeb919f4 100644
--- a/homeassistant/components/heos/services.yaml
+++ b/homeassistant/components/heos/services.yaml
@@ -1,3 +1,17 @@
+group_volume_set:
+  target:
+    entity:
+      integration: heos
+      domain: media_player
+  fields:
+    volume_level:
+      required: true
+      selector:
+        number:
+          min: 0
+          max: 1
+          step: 0.01
+
 sign_in:
   fields:
     username:
diff --git a/homeassistant/components/heos/strings.json b/homeassistant/components/heos/strings.json
index 53e20a032b5..af70c0c786e 100644
--- a/homeassistant/components/heos/strings.json
+++ b/homeassistant/components/heos/strings.json
@@ -71,6 +71,16 @@
     }
   },
   "services": {
+    "group_volume_set": {
+      "name": "Set group volume",
+      "description": "Sets the group's volume while preserving member volume ratios.",
+      "fields": {
+        "volume_level": {
+          "name": "Level",
+          "description": "The volume. 0 is inaudible, 1 is the maximum volume."
+        }
+      }
+    },
     "sign_in": {
       "name": "Sign in",
       "description": "Signs in to a HEOS account.",
@@ -94,6 +104,9 @@
     "action_error": {
       "message": "Unable to {action}: {error}"
     },
+    "entity_not_grouped": {
+      "message": "Entity {entity_id} is not joined to a group"
+    },
     "entity_not_found": {
       "message": "Entity {entity_id} was not found"
     },
diff --git a/tests/components/heos/__init__.py b/tests/components/heos/__init__.py
index cf0d10790b7..bc72981d805 100644
--- a/tests/components/heos/__init__.py
+++ b/tests/components/heos/__init__.py
@@ -34,6 +34,7 @@ class MockHeos(Heos):
         self.player_set_play_state: AsyncMock = AsyncMock()
         self.player_set_volume: AsyncMock = AsyncMock()
         self.set_group: AsyncMock = AsyncMock()
+        self.set_group_volume: AsyncMock = AsyncMock()
         self.sign_in: AsyncMock = AsyncMock()
         self.sign_out: AsyncMock = AsyncMock()
 
diff --git a/tests/components/heos/test_media_player.py b/tests/components/heos/test_media_player.py
index 3768462eada..5a0ed0aa7c4 100644
--- a/tests/components/heos/test_media_player.py
+++ b/tests/components/heos/test_media_player.py
@@ -22,7 +22,7 @@ import pytest
 from syrupy.assertion import SnapshotAssertion
 from syrupy.filters import props
 
-from homeassistant.components.heos.const import DOMAIN
+from homeassistant.components.heos.const import DOMAIN, SERVICE_GROUP_VOLUME_SET
 from homeassistant.components.media_player import (
     ATTR_GROUP_MEMBERS,
     ATTR_INPUT_SOURCE,
@@ -724,6 +724,62 @@ async def test_volume_set_error(
     controller.player_set_volume.assert_called_once_with(1, 100)
 
 
+async def test_group_volume_set(
+    hass: HomeAssistant, config_entry: MockConfigEntry, controller: MockHeos
+) -> None:
+    """Test the group volume set service."""
+    config_entry.add_to_hass(hass)
+    await hass.config_entries.async_setup(config_entry.entry_id)
+    await hass.services.async_call(
+        DOMAIN,
+        SERVICE_GROUP_VOLUME_SET,
+        {ATTR_ENTITY_ID: "media_player.test_player", ATTR_MEDIA_VOLUME_LEVEL: 1},
+        blocking=True,
+    )
+    controller.set_group_volume.assert_called_once_with(999, 100)
+
+
+async def test_group_volume_set_error(
+    hass: HomeAssistant, config_entry: MockConfigEntry, controller: MockHeos
+) -> None:
+    """Test the group volume set service errors."""
+    config_entry.add_to_hass(hass)
+    await hass.config_entries.async_setup(config_entry.entry_id)
+    controller.set_group_volume.side_effect = CommandFailedError("", "Failure", 1)
+    with pytest.raises(
+        HomeAssistantError,
+        match=re.escape("Unable to set group volume level: Failure (1)"),
+    ):
+        await hass.services.async_call(
+            DOMAIN,
+            SERVICE_GROUP_VOLUME_SET,
+            {ATTR_ENTITY_ID: "media_player.test_player", ATTR_MEDIA_VOLUME_LEVEL: 1},
+            blocking=True,
+        )
+    controller.set_group_volume.assert_called_once_with(999, 100)
+
+
+async def test_group_volume_set_not_grouped_error(
+    hass: HomeAssistant, config_entry: MockConfigEntry, controller: MockHeos
+) -> None:
+    """Test the group volume set service when not grouped raises error."""
+    config_entry.add_to_hass(hass)
+    await hass.config_entries.async_setup(config_entry.entry_id)
+    player = controller.players[1]
+    player.group_id = None
+    with pytest.raises(
+        ServiceValidationError,
+        match=re.escape("Entity media_player.test_player is not joined to a group"),
+    ):
+        await hass.services.async_call(
+            DOMAIN,
+            SERVICE_GROUP_VOLUME_SET,
+            {ATTR_ENTITY_ID: "media_player.test_player", ATTR_MEDIA_VOLUME_LEVEL: 1},
+            blocking=True,
+        )
+    controller.set_group_volume.assert_not_called()
+
+
 async def test_select_favorite(
     hass: HomeAssistant,
     config_entry: MockConfigEntry,