diff --git a/moto/iot/models.py b/moto/iot/models.py
--- a/moto/iot/models.py
+++ b/moto/iot/models.py
@@ -8,7 +8,7 @@
 from cryptography.hazmat.primitives.asymmetric import rsa
 from cryptography.hazmat.primitives import serialization, hashes
 from datetime import datetime, timedelta
-from typing import Any, Dict, List, Tuple, Optional, Pattern, Iterable
+from typing import Any, Dict, List, Tuple, Optional, Pattern, Iterable, TYPE_CHECKING
 
 from .utils import PAGINATION_MODEL
 
@@ -27,6 +27,9 @@
     ThingStillAttached,
 )
 
+if TYPE_CHECKING:
+    from moto.iotdata.models import FakeShadow
+
 
 class FakeThing(BaseModel):
     def __init__(
@@ -46,7 +49,7 @@ def __init__(
         # TODO: we need to handle "version"?
 
         # for iot-data
-        self.thing_shadow: Any = None
+        self.thing_shadows: Dict[Optional[str], FakeShadow] = {}
 
     def matches(self, query_string: str) -> bool:
         if query_string == "*":
diff --git a/moto/iotdata/models.py b/moto/iotdata/models.py
--- a/moto/iotdata/models.py
+++ b/moto/iotdata/models.py
@@ -154,7 +154,9 @@ def __init__(self, region_name: str, account_id: str):
     def iot_backend(self) -> IoTBackend:
         return iot_backends[self.account_id][self.region_name]
 
-    def update_thing_shadow(self, thing_name: str, payload: str) -> FakeShadow:
+    def update_thing_shadow(
+        self, thing_name: str, payload: str, shadow_name: Optional[str]
+    ) -> FakeShadow:
         """
         spec of payload:
           - need node `state`
@@ -175,34 +177,43 @@ def update_thing_shadow(self, thing_name: str, payload: str) -> FakeShadow:
         if any(_ for _ in _payload["state"].keys() if _ not in ["desired", "reported"]):
             raise InvalidRequestException("State contains an invalid node")
 
-        if "version" in _payload and thing.thing_shadow.version != _payload["version"]:
+        thing_shadow = thing.thing_shadows.get(shadow_name)
+        if "version" in _payload and thing_shadow.version != _payload["version"]:  # type: ignore
             raise ConflictException("Version conflict")
-        new_shadow = FakeShadow.create_from_previous_version(
-            thing.thing_shadow, _payload
-        )
-        thing.thing_shadow = new_shadow
-        return thing.thing_shadow
+        new_shadow = FakeShadow.create_from_previous_version(thing_shadow, _payload)
+        thing.thing_shadows[shadow_name] = new_shadow
+        return new_shadow
 
-    def get_thing_shadow(self, thing_name: str) -> FakeShadow:
+    def get_thing_shadow(
+        self, thing_name: str, shadow_name: Optional[str]
+    ) -> FakeShadow:
         thing = self.iot_backend.describe_thing(thing_name)
+        thing_shadow = thing.thing_shadows.get(shadow_name)
 
-        if thing.thing_shadow is None or thing.thing_shadow.deleted:
+        if thing_shadow is None or thing_shadow.deleted:
             raise ResourceNotFoundException()
-        return thing.thing_shadow
+        return thing_shadow
 
-    def delete_thing_shadow(self, thing_name: str) -> FakeShadow:
+    def delete_thing_shadow(
+        self, thing_name: str, shadow_name: Optional[str]
+    ) -> FakeShadow:
         thing = self.iot_backend.describe_thing(thing_name)
-        if thing.thing_shadow is None:
+        thing_shadow = thing.thing_shadows.get(shadow_name)
+        if thing_shadow is None:
             raise ResourceNotFoundException()
         payload = None
-        new_shadow = FakeShadow.create_from_previous_version(
-            thing.thing_shadow, payload
-        )
-        thing.thing_shadow = new_shadow
-        return thing.thing_shadow
+        new_shadow = FakeShadow.create_from_previous_version(thing_shadow, payload)
+        thing.thing_shadows[shadow_name] = new_shadow
+        return new_shadow
 
     def publish(self, topic: str, payload: str) -> None:
         self.published_payloads.append((topic, payload))
 
+    def list_named_shadows_for_thing(self, thing_name: str) -> List[FakeShadow]:
+        thing = self.iot_backend.describe_thing(thing_name)
+        return [
+            shadow for name, shadow in thing.thing_shadows.items() if name is not None
+        ]
+
 
 iotdata_backends = BackendDict(IoTDataPlaneBackend, "iot")
diff --git a/moto/iotdata/responses.py b/moto/iotdata/responses.py
--- a/moto/iotdata/responses.py
+++ b/moto/iotdata/responses.py
@@ -26,20 +26,28 @@ def iotdata_backend(self) -> IoTDataPlaneBackend:
 
     def update_thing_shadow(self) -> str:
         thing_name = self._get_param("thingName")
-        payload = self.body
+        shadow_name = self.querystring.get("name", [None])[0]
         payload = self.iotdata_backend.update_thing_shadow(
-            thing_name=thing_name, payload=payload
+            thing_name=thing_name,
+            payload=self.body,
+            shadow_name=shadow_name,
         )
         return json.dumps(payload.to_response_dict())
 
     def get_thing_shadow(self) -> str:
         thing_name = self._get_param("thingName")
-        payload = self.iotdata_backend.get_thing_shadow(thing_name=thing_name)
+        shadow_name = self.querystring.get("name", [None])[0]
+        payload = self.iotdata_backend.get_thing_shadow(
+            thing_name=thing_name, shadow_name=shadow_name
+        )
         return json.dumps(payload.to_dict())
 
     def delete_thing_shadow(self) -> str:
         thing_name = self._get_param("thingName")
-        payload = self.iotdata_backend.delete_thing_shadow(thing_name=thing_name)
+        shadow_name = self.querystring.get("name", [None])[0]
+        payload = self.iotdata_backend.delete_thing_shadow(
+            thing_name=thing_name, shadow_name=shadow_name
+        )
         return json.dumps(payload.to_dict())
 
     def publish(self) -> str:
@@ -49,3 +57,8 @@ def publish(self) -> str:
         topic = unquote(topic) if "%" in topic else topic
         self.iotdata_backend.publish(topic=topic, payload=self.body)
         return json.dumps(dict())
+
+    def list_named_shadows_for_thing(self) -> str:
+        thing_name = self._get_param("thingName")
+        shadows = self.iotdata_backend.list_named_shadows_for_thing(thing_name)
+        return json.dumps({"results": [shadow.to_dict() for shadow in shadows]})

Hi @AngeloGC, happy to hear that Moto is useful for you!

Marking it as an enhancement to support this.
diff --git a/tests/test_iotdata/test_iotdata.py b/tests/test_iotdata/test_iotdata.py
--- a/tests/test_iotdata/test_iotdata.py
+++ b/tests/test_iotdata/test_iotdata.py
@@ -93,6 +93,61 @@ def test_update():
     assert ex.value.response["Error"]["Message"] == "Version conflict"
 
 
+@mock_iot
+@mock_iotdata
+def test_create_named_shadows():
+    iot_client = boto3.client("iot", region_name="ap-northeast-1")
+    client = boto3.client("iot-data", region_name="ap-northeast-1")
+    thing_name = "my-thing"
+    iot_client.create_thing(thingName=thing_name)
+
+    # default shadow
+    default_payload = json.dumps({"state": {"desired": {"name": "default"}}})
+    res = client.update_thing_shadow(thingName=thing_name, payload=default_payload)
+    payload = json.loads(res["payload"].read())
+    assert payload["state"] == {"desired": {"name": "default"}}
+
+    # Create named shadows
+    for name in ["shadow1", "shadow2"]:
+        named_payload = json.dumps({"state": {"reported": {"name": name}}}).encode(
+            "utf-8"
+        )
+        client.update_thing_shadow(
+            thingName=thing_name, payload=named_payload, shadowName=name
+        )
+
+        res = client.get_thing_shadow(thingName=thing_name, shadowName=name)
+        payload = json.loads(res["payload"].read())
+        assert payload["state"]["reported"] == {"name": name}
+
+    # List named shadows
+    shadows = client.list_named_shadows_for_thing(thingName=thing_name)["results"]
+    assert len(shadows) == 2
+
+    for shadow in shadows:
+        shadow.pop("metadata")
+        shadow.pop("timestamp")
+        shadow.pop("version")
+
+    # Verify both named shadows are present
+    for name in ["shadow1", "shadow2"]:
+        assert {
+            "state": {"reported": {"name": name}, "delta": {"name": name}}
+        } in shadows
+
+    # Verify we can delete a named shadow
+    client.delete_thing_shadow(thingName=thing_name, shadowName="shadow2")
+
+    with pytest.raises(ClientError):
+        client.get_thing_shadow(thingName="shadow1")
+
+    # The default and other named shadow are still there
+    assert "payload" in client.get_thing_shadow(thingName=thing_name)
+    assert "payload" in client.get_thing_shadow(
+        thingName=thing_name, shadowName="shadow1"
+    )
+
+
 @mock_iotdata
 def test_publish():
     region_name = "ap-northeast-1"

Feature request: Add support for named shadows in iot things
Hello team!

I have been using the moto library the past few days, and so far is amazing! It has allowed me to test code using aws services more quickly.

However, I have noticed that the mocking implementation for iot does not allow to store named shadows, only the classic one. It would be great if someone implements such a feature in the future.

tests/test_iotdata/test_iotdata.py::test_create_named_shadows
tests/test_iotdata/test_iotdata.py::test_publish tests/test_iotdata/test_iotdata.py::test_basic tests/test_iotdata/test_iotdata.py::test_update tests/test_iotdata/test_iotdata.py::test_delete_field_from_device_shadow