diff --git a/homeassistant/components/google_assistant/trait.py b/homeassistant/components/google_assistant/trait.py
index 55c26b9499d..b8d21c0c77b 100644
--- a/homeassistant/components/google_assistant/trait.py
+++ b/homeassistant/components/google_assistant/trait.py
@@ -68,7 +68,6 @@ from .const import (
     ERR_ALREADY_ARMED,
     ERR_ALREADY_DISARMED,
     ERR_CHALLENGE_NOT_SETUP,
-    ERR_FUNCTION_NOT_SUPPORTED,
     ERR_NOT_SUPPORTED,
     ERR_UNSUPPORTED_INPUT,
     ERR_VALUE_OUT_OF_RANGE,
@@ -120,6 +119,7 @@ COMMAND_INPUT = f"{PREFIX_COMMANDS}SetInput"
 COMMAND_NEXT_INPUT = f"{PREFIX_COMMANDS}NextInput"
 COMMAND_PREVIOUS_INPUT = f"{PREFIX_COMMANDS}PreviousInput"
 COMMAND_OPENCLOSE = f"{PREFIX_COMMANDS}OpenClose"
+COMMAND_OPENCLOSE_RELATIVE = f"{PREFIX_COMMANDS}OpenCloseRelative"
 COMMAND_SET_VOLUME = f"{PREFIX_COMMANDS}setVolume"
 COMMAND_VOLUME_RELATIVE = f"{PREFIX_COMMANDS}volumeRelative"
 COMMAND_MUTE = f"{PREFIX_COMMANDS}mute"
@@ -1519,7 +1519,7 @@ class OpenCloseTrait(_Trait):
     )
 
     name = TRAIT_OPENCLOSE
-    commands = [COMMAND_OPENCLOSE]
+    commands = [COMMAND_OPENCLOSE, COMMAND_OPENCLOSE_RELATIVE]
 
     @staticmethod
     def supported(domain, features, device_class):
@@ -1543,9 +1543,20 @@ class OpenCloseTrait(_Trait):
     def sync_attributes(self):
         """Return opening direction."""
         response = {}
+        features = self.state.attributes.get(ATTR_SUPPORTED_FEATURES, 0)
+
         if self.state.domain == binary_sensor.DOMAIN:
             response["queryOnlyOpenClose"] = True
             response["discreteOnlyOpenClose"] = True
+        elif self.state.domain == cover.DOMAIN:
+            if features & cover.SUPPORT_SET_POSITION == 0:
+                response["discreteOnlyOpenClose"] = True
+
+                if (
+                    features & cover.SUPPORT_OPEN == 0
+                    and features & cover.SUPPORT_CLOSE == 0
+                ):
+                    response["queryOnlyOpenClose"] = True
 
         if self.state.attributes.get(ATTR_ASSUMED_STATE):
             response["commandOnlyOpenClose"] = True
@@ -1590,26 +1601,36 @@ class OpenCloseTrait(_Trait):
     async def execute(self, command, data, params, challenge):
         """Execute an Open, close, Set position command."""
         domain = self.state.domain
+        features = self.state.attributes.get(ATTR_SUPPORTED_FEATURES, 0)
 
         if domain == cover.DOMAIN:
             svc_params = {ATTR_ENTITY_ID: self.state.entity_id}
+            should_verify = False
+            if command == COMMAND_OPENCLOSE_RELATIVE:
+                position = self.state.attributes.get(cover.ATTR_CURRENT_POSITION)
+                if position is None:
+                    raise SmartHomeError(
+                        ERR_NOT_SUPPORTED,
+                        "Current position not know for relative command",
+                    )
+                position = max(0, min(100, position + params["openRelativePercent"]))
+            else:
+                position = params["openPercent"]
 
-            if params["openPercent"] == 0:
+            if features & cover.SUPPORT_SET_POSITION:
+                service = cover.SERVICE_SET_COVER_POSITION
+                if position > 0:
+                    should_verify = True
+                svc_params[cover.ATTR_POSITION] = position
+            elif position == 0:
                 service = cover.SERVICE_CLOSE_COVER
                 should_verify = False
-            elif params["openPercent"] == 100:
+            elif position == 100:
                 service = cover.SERVICE_OPEN_COVER
                 should_verify = True
-            elif (
-                self.state.attributes.get(ATTR_SUPPORTED_FEATURES, 0)
-                & cover.SUPPORT_SET_POSITION
-            ):
-                service = cover.SERVICE_SET_COVER_POSITION
-                should_verify = True
-                svc_params[cover.ATTR_POSITION] = params["openPercent"]
             else:
                 raise SmartHomeError(
-                    ERR_FUNCTION_NOT_SUPPORTED, "Setting a position is not supported"
+                    ERR_NOT_SUPPORTED, "No support for partial open close"
                 )
 
             if (
diff --git a/tests/components/google_assistant/test_smart_home.py b/tests/components/google_assistant/test_smart_home.py
index f35415ee9e4..3fcab2dc2a2 100644
--- a/tests/components/google_assistant/test_smart_home.py
+++ b/tests/components/google_assistant/test_smart_home.py
@@ -839,7 +839,7 @@ async def test_device_class_cover(hass, device_class, google_type):
             "agentUserId": "test-agent",
             "devices": [
                 {
-                    "attributes": {},
+                    "attributes": {"discreteOnlyOpenClose": True},
                     "id": "cover.demo_sensor",
                     "name": {"name": "Demo Sensor"},
                     "traits": ["action.devices.traits.OpenClose"],
diff --git a/tests/components/google_assistant/test_trait.py b/tests/components/google_assistant/test_trait.py
index a579eebea04..2ca2e6c8e6c 100644
--- a/tests/components/google_assistant/test_trait.py
+++ b/tests/components/google_assistant/test_trait.py
@@ -1860,8 +1860,12 @@ async def test_openclose_cover(hass):
 
     calls = async_mock_service(hass, cover.DOMAIN, cover.SERVICE_SET_COVER_POSITION)
     await trt.execute(trait.COMMAND_OPENCLOSE, BASIC_DATA, {"openPercent": 50}, {})
-    assert len(calls) == 1
+    await trt.execute(
+        trait.COMMAND_OPENCLOSE_RELATIVE, BASIC_DATA, {"openRelativePercent": 50}, {}
+    )
+    assert len(calls) == 2
     assert calls[0].data == {ATTR_ENTITY_ID: "cover.bla", cover.ATTR_POSITION: 50}
+    assert calls[1].data == {ATTR_ENTITY_ID: "cover.bla", cover.ATTR_POSITION: 100}
 
 
 async def test_openclose_cover_unknown_state(hass):
@@ -1873,10 +1877,14 @@ async def test_openclose_cover_unknown_state(hass):
 
     # No state
     trt = trait.OpenCloseTrait(
-        hass, State("cover.bla", STATE_UNKNOWN, {}), BASIC_CONFIG
+        hass,
+        State(
+            "cover.bla", STATE_UNKNOWN, {ATTR_SUPPORTED_FEATURES: cover.SUPPORT_OPEN}
+        ),
+        BASIC_CONFIG,
     )
 
-    assert trt.sync_attributes() == {}
+    assert trt.sync_attributes() == {"discreteOnlyOpenClose": True}
 
     with pytest.raises(helpers.SmartHomeError):
         trt.query_attributes()
@@ -1920,25 +1928,81 @@ async def test_openclose_cover_assumed_state(hass):
     assert calls[0].data == {ATTR_ENTITY_ID: "cover.bla", cover.ATTR_POSITION: 40}
 
 
+async def test_openclose_cover_query_only(hass):
+    """Test OpenClose trait support for cover domain."""
+    assert helpers.get_google_type(cover.DOMAIN, None) is not None
+    assert trait.OpenCloseTrait.supported(cover.DOMAIN, 0, None)
+
+    state = State(
+        "cover.bla",
+        cover.STATE_OPEN,
+    )
+
+    trt = trait.OpenCloseTrait(
+        hass,
+        state,
+        BASIC_CONFIG,
+    )
+
+    assert trt.sync_attributes() == {
+        "discreteOnlyOpenClose": True,
+        "queryOnlyOpenClose": True,
+    }
+    assert trt.query_attributes() == {"openPercent": 100}
+
+
 async def test_openclose_cover_no_position(hass):
     """Test OpenClose trait support for cover domain."""
     assert helpers.get_google_type(cover.DOMAIN, None) is not None
     assert trait.OpenCloseTrait.supported(
-        cover.DOMAIN, cover.SUPPORT_SET_POSITION, None
+        cover.DOMAIN, cover.SUPPORT_OPEN | cover.SUPPORT_CLOSE, None
+    )
+
+    state = State(
+        "cover.bla",
+        cover.STATE_OPEN,
+        {
+            ATTR_SUPPORTED_FEATURES: cover.SUPPORT_OPEN | cover.SUPPORT_CLOSE,
+        },
     )
 
     trt = trait.OpenCloseTrait(
-        hass, State("cover.bla", cover.STATE_OPEN, {}), BASIC_CONFIG
+        hass,
+        state,
+        BASIC_CONFIG,
     )
 
-    assert trt.sync_attributes() == {}
+    assert trt.sync_attributes() == {"discreteOnlyOpenClose": True}
     assert trt.query_attributes() == {"openPercent": 100}
 
+    state.state = cover.STATE_CLOSED
+
+    assert trt.sync_attributes() == {"discreteOnlyOpenClose": True}
+    assert trt.query_attributes() == {"openPercent": 0}
+
     calls = async_mock_service(hass, cover.DOMAIN, cover.SERVICE_CLOSE_COVER)
     await trt.execute(trait.COMMAND_OPENCLOSE, BASIC_DATA, {"openPercent": 0}, {})
     assert len(calls) == 1
     assert calls[0].data == {ATTR_ENTITY_ID: "cover.bla"}
 
+    calls = async_mock_service(hass, cover.DOMAIN, cover.SERVICE_OPEN_COVER)
+    await trt.execute(trait.COMMAND_OPENCLOSE, BASIC_DATA, {"openPercent": 100}, {})
+    assert len(calls) == 1
+    assert calls[0].data == {ATTR_ENTITY_ID: "cover.bla"}
+
+    with pytest.raises(
+        SmartHomeError, match=r"Current position not know for relative command"
+    ):
+        await trt.execute(
+            trait.COMMAND_OPENCLOSE_RELATIVE,
+            BASIC_DATA,
+            {"openRelativePercent": 100},
+            {},
+        )
+
+    with pytest.raises(SmartHomeError, match=r"No support for partial open close"):
+        await trt.execute(trait.COMMAND_OPENCLOSE, BASIC_DATA, {"openPercent": 50}, {})
+
 
 @pytest.mark.parametrize(
     "device_class",
@@ -1996,10 +2060,9 @@ async def test_openclose_cover_secure(hass, device_class):
     assert calls[0].data == {ATTR_ENTITY_ID: "cover.bla", cover.ATTR_POSITION: 50}
 
     # no challenge on close
-    calls = async_mock_service(hass, cover.DOMAIN, cover.SERVICE_CLOSE_COVER)
     await trt.execute(trait.COMMAND_OPENCLOSE, PIN_DATA, {"openPercent": 0}, {})
-    assert len(calls) == 1
-    assert calls[0].data == {ATTR_ENTITY_ID: "cover.bla"}
+    assert len(calls) == 2
+    assert calls[1].data == {ATTR_ENTITY_ID: "cover.bla", cover.ATTR_POSITION: 0}
 
 
 @pytest.mark.parametrize(