diff --git a/homeassistant/components/shelly/sensor.py b/homeassistant/components/shelly/sensor.py
index 183a1aa06a1..0020c6e0614 100644
--- a/homeassistant/components/shelly/sensor.py
+++ b/homeassistant/components/shelly/sensor.py
@@ -374,9 +374,9 @@ SENSORS: dict[tuple[str, str], BlockSensorDescription] = {
         key="sensor|sensorOp",
         name="Operation",
         device_class=SensorDeviceClass.ENUM,
-        options=["unknown", "warmup", "normal", "fault"],
+        options=["warmup", "normal", "fault"],
         translation_key="operation",
-        value=lambda value: value,
+        value=lambda value: None if value == "unknown" else value,
         extra_state_attributes=lambda block: {"self_test": block.selfTest},
     ),
     ("valve", "valve"): BlockSensorDescription(
@@ -391,8 +391,8 @@ SENSORS: dict[tuple[str, str], BlockSensorDescription] = {
             "failure",
             "opened",
             "opening",
-            "unknown",
         ],
+        value=lambda value: None if value == "unknown" else value,
         entity_category=EntityCategory.DIAGNOSTIC,
         removal_condition=lambda _, block: block.valve == "not_connected",
     ),
diff --git a/homeassistant/components/shelly/strings.json b/homeassistant/components/shelly/strings.json
index eb869b54e4c..cc511c93afe 100644
--- a/homeassistant/components/shelly/strings.json
+++ b/homeassistant/components/shelly/strings.json
@@ -106,7 +106,6 @@
         "state_attributes": {
           "detected": {
             "state": {
-              "unknown": "Unknown",
               "none": "None",
               "mild": "Mild",
               "heavy": "Heavy",
@@ -141,7 +140,6 @@
     "sensor": {
       "operation": {
         "state": {
-          "unknown": "Unknown",
           "warmup": "Warm-up",
           "normal": "Normal",
           "fault": "Fault"
@@ -164,8 +162,7 @@
           "closing": "Closing",
           "failure": "Failure",
           "opened": "Opened",
-          "opening": "Opening",
-          "unknown": "[%key:component::shelly::entity::sensor::operation::state::unknown%]"
+          "opening": "Opening"
         }
       }
     }
diff --git a/tests/components/shelly/conftest.py b/tests/components/shelly/conftest.py
index 8ea04ea3bfb..5c0f912b72d 100644
--- a/tests/components/shelly/conftest.py
+++ b/tests/components/shelly/conftest.py
@@ -134,11 +134,18 @@ MOCK_BLOCKS = [
         set_state=AsyncMock(side_effect=mock_light_set_state),
     ),
     Mock(
-        sensor_ids={"motion": 0, "temp": 22.1, "gas": "mild", "motionActive": 1},
+        sensor_ids={
+            "motion": 0,
+            "temp": 22.1,
+            "gas": "mild",
+            "motionActive": 1,
+            "sensorOp": "normal",
+        },
         channel="0",
         motion=0,
         temp=22.1,
         gas="mild",
+        sensorOp="normal",
         targetTemp=4,
         description="sensor_0",
         type="sensor",
diff --git a/tests/components/shelly/test_sensor.py b/tests/components/shelly/test_sensor.py
index d0fec65c7de..d37a146e314 100644
--- a/tests/components/shelly/test_sensor.py
+++ b/tests/components/shelly/test_sensor.py
@@ -345,14 +345,30 @@ async def test_block_sensor_without_value(
     assert hass.states.get(entity_id) is None
 
 
+@pytest.mark.parametrize(
+    ("entity", "initial_state", "block_id", "attribute", "value"),
+    [
+        ("test_name_battery", "98", DEVICE_BLOCK_ID, "battery", None),
+        ("test_name_operation", "normal", SENSOR_BLOCK_ID, "sensorOp", "unknown"),
+    ],
+)
 async def test_block_sensor_unknown_value(
-    hass: HomeAssistant, mock_block_device: Mock, monkeypatch: pytest.MonkeyPatch
+    hass: HomeAssistant,
+    mock_block_device: Mock,
+    monkeypatch: pytest.MonkeyPatch,
+    entity: str,
+    initial_state: str,
+    block_id: int,
+    attribute: str,
+    value: str | None,
 ) -> None:
     """Test block sensor unknown value."""
-    entity_id = f"{SENSOR_DOMAIN}.test_name_battery"
+    entity_id = f"{SENSOR_DOMAIN}.{entity}"
     await init_integration(hass, 1)
 
-    monkeypatch.setattr(mock_block_device.blocks[DEVICE_BLOCK_ID], "battery", None)
+    assert hass.states.get(entity_id).state == initial_state
+
+    monkeypatch.setattr(mock_block_device.blocks[block_id], attribute, value)
     mock_block_device.mock_update()
 
     assert hass.states.get(entity_id).state == STATE_UNKNOWN