diff --git a/homeassistant/components/group/fan.py b/homeassistant/components/group/fan.py
index 4ee788c8402..4e3bb824266 100644
--- a/homeassistant/components/group/fan.py
+++ b/homeassistant/components/group/fan.py
@@ -25,7 +25,6 @@ from homeassistant.components.fan import (
 )
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import (
-    ATTR_ASSUMED_STATE,
     ATTR_ENTITY_ID,
     ATTR_SUPPORTED_FEATURES,
     CONF_ENTITIES,
@@ -41,12 +40,7 @@ from homeassistant.helpers.entity_platform import AddEntitiesCallback
 from homeassistant.helpers.typing import ConfigType, DiscoveryInfoType
 
 from . import GroupEntity
-from .util import (
-    attribute_equal,
-    most_frequent_attribute,
-    reduce_attribute,
-    states_equal,
-)
+from .util import attribute_equal, most_frequent_attribute, reduce_attribute
 
 SUPPORTED_FLAGS = {
     FanEntityFeature.SET_SPEED,
@@ -110,7 +104,6 @@ class FanGroup(GroupEntity, FanEntity):
     """Representation of a FanGroup."""
 
     _attr_available: bool = False
-    _attr_assumed_state: bool = True
 
     def __init__(self, unique_id: str | None, name: str, entities: list[str]) -> None:
         """Initialize a FanGroup entity."""
@@ -243,19 +236,16 @@ class FanGroup(GroupEntity, FanEntity):
         """Set an attribute based on most frequent supported entities attributes."""
         states = self._async_states_by_support_flag(flag)
         setattr(self, attr, most_frequent_attribute(states, entity_attr))
-        self._attr_assumed_state |= not attribute_equal(states, entity_attr)
 
     @callback
     def async_update_group_state(self) -> None:
         """Update state and attributes."""
-        self._attr_assumed_state = False
 
         states = [
             state
             for entity_id in self._entity_ids
             if (state := self.hass.states.get(entity_id)) is not None
         ]
-        self._attr_assumed_state |= not states_equal(states)
 
         # Set group as unavailable if all members are unavailable or missing
         self._attr_available = any(state.state != STATE_UNAVAILABLE for state in states)
@@ -274,9 +264,6 @@ class FanGroup(GroupEntity, FanEntity):
             FanEntityFeature.SET_SPEED
         )
         self._percentage = reduce_attribute(percentage_states, ATTR_PERCENTAGE)
-        self._attr_assumed_state |= not attribute_equal(
-            percentage_states, ATTR_PERCENTAGE
-        )
         if (
             percentage_states
             and percentage_states[0].attributes.get(ATTR_PERCENTAGE_STEP)
@@ -301,6 +288,3 @@ class FanGroup(GroupEntity, FanEntity):
                 ior, [feature for feature in SUPPORTED_FLAGS if self._fans[feature]], 0
             )
         )
-        self._attr_assumed_state |= any(
-            state.attributes.get(ATTR_ASSUMED_STATE) for state in states
-        )
diff --git a/tests/components/group/test_config_flow.py b/tests/components/group/test_config_flow.py
index d0e90fe61bd..1c8275c7f2d 100644
--- a/tests/components/group/test_config_flow.py
+++ b/tests/components/group/test_config_flow.py
@@ -468,7 +468,7 @@ async def test_options_flow_hides_members(
 
 COVER_ATTRS = [{"supported_features": 0}, {}]
 EVENT_ATTRS = [{"event_types": []}, {"event_type": None}]
-FAN_ATTRS = [{"supported_features": 0}, {"assumed_state": True}]
+FAN_ATTRS = [{"supported_features": 0}, {}]
 LIGHT_ATTRS = [
     {
         "icon": "mdi:lightbulb-group",
diff --git a/tests/components/group/test_fan.py b/tests/components/group/test_fan.py
index 6269df3fed7..2272a29f6ed 100644
--- a/tests/components/group/test_fan.py
+++ b/tests/components/group/test_fan.py
@@ -247,11 +247,7 @@ async def test_attributes(hass: HomeAssistant, setup_comp) -> None:
     assert state.attributes[ATTR_PERCENTAGE] == 50
     assert ATTR_ASSUMED_STATE not in state.attributes
 
-    # Add Entity that supports
-    # ### Test assumed state ###
-    # ##########################
-
-    # Add Entity with a different speed should set assumed state
+    # Add Entity with a different speed should not set assumed state
     hass.states.async_set(
         PERCENTAGE_LIMITED_FAN_ENTITY_ID,
         STATE_ON,
@@ -264,7 +260,7 @@ async def test_attributes(hass: HomeAssistant, setup_comp) -> None:
 
     state = hass.states.get(FAN_GROUP)
     assert state.state == STATE_ON
-    assert state.attributes[ATTR_ASSUMED_STATE] is True
+    assert ATTR_ASSUMED_STATE not in state.attributes
     assert state.attributes[ATTR_PERCENTAGE] == int((50 + 75) / 2)
 
 
@@ -306,11 +302,7 @@ async def test_direction_oscillating(hass: HomeAssistant, setup_comp) -> None:
     assert state.attributes[ATTR_DIRECTION] == DIRECTION_FORWARD
     assert ATTR_ASSUMED_STATE not in state.attributes
 
-    # Add Entity that supports
-    # ### Test assumed state ###
-    # ##########################
-
-    # Add Entity with a different direction should set assumed state
+    # Add Entity with a different direction should not set assumed state
     hass.states.async_set(
         PERCENTAGE_FULL_FAN_ENTITY_ID,
         STATE_ON,
@@ -325,11 +317,10 @@ async def test_direction_oscillating(hass: HomeAssistant, setup_comp) -> None:
 
     state = hass.states.get(FAN_GROUP)
     assert state.state == STATE_ON
-    assert state.attributes[ATTR_ASSUMED_STATE] is True
+    assert ATTR_ASSUMED_STATE not in state.attributes
     assert ATTR_PERCENTAGE in state.attributes
     assert state.attributes[ATTR_PERCENTAGE] == 50
     assert state.attributes[ATTR_OSCILLATING] is True
-    assert ATTR_ASSUMED_STATE in state.attributes
 
     # Now that everything is the same, no longer assumed state