diff --git a/tests/components/mqtt/test_config_flow.py b/tests/components/mqtt/test_config_flow.py
index 1253a4d5f9b..0dd80e8b11b 100644
--- a/tests/components/mqtt/test_config_flow.py
+++ b/tests/components/mqtt/test_config_flow.py
@@ -783,7 +783,7 @@ async def test_invalid_discovery_prefix(
     mqtt_mock_entry_no_yaml_config: MqttMockHAClientGenerator,
     mock_try_connection,
     mock_reload_after_entry_update,
-) -> HomeAssistant:
+) -> None:
     """Test setting an invalid discovery prefix."""
     mqtt_mock = await mqtt_mock_entry_no_yaml_config()
     mock_try_connection.return_value = True
@@ -1160,7 +1160,7 @@ async def test_try_connection_with_advanced_parameters(
     tmp_path: Path,
     mock_ssl_context,
     mock_process_uploaded_file,
-) -> HomeAssistant:
+) -> None:
     """Test config flow with advanced parameters from config."""
 
     with open(tmp_path / "client.crt", "wb") as certfile:
diff --git a/tests/components/mqtt/test_device_trigger.py b/tests/components/mqtt/test_device_trigger.py
index 18e90121999..4616627c61f 100644
--- a/tests/components/mqtt/test_device_trigger.py
+++ b/tests/components/mqtt/test_device_trigger.py
@@ -10,7 +10,7 @@ import homeassistant.components.automation as automation
 from homeassistant.components.device_automation import DeviceAutomationType
 from homeassistant.components.mqtt import _LOGGER, DOMAIN, debug_info
 from homeassistant.const import Platform
-from homeassistant.core import HomeAssistant
+from homeassistant.core import HomeAssistant, ServiceCall
 from homeassistant.helpers import device_registry as dr
 from homeassistant.helpers.trigger import async_initialize_triggers
 from homeassistant.setup import async_setup_component
@@ -28,7 +28,7 @@ from tests.typing import MqttMockHAClient, MqttMockHAClientGenerator, WebSocketG
 
 
 @pytest.fixture
-def calls(hass):
+def calls(hass: HomeAssistant) -> list[ServiceCall]:
     """Track calls to a mock service."""
     return async_mock_service(hass, "test", "automation")
 
diff --git a/tests/components/mqtt/test_light_json.py b/tests/components/mqtt/test_light_json.py
index cc14d9cd661..80d26788bf8 100644
--- a/tests/components/mqtt/test_light_json.py
+++ b/tests/components/mqtt/test_light_json.py
@@ -79,7 +79,6 @@ light:
   brightness_scale: 99
 """
 import copy
-import json
 from pathlib import Path
 from unittest.mock import call, patch
 
@@ -98,6 +97,7 @@ from homeassistant.const import (
     Platform,
 )
 from homeassistant.core import HomeAssistant, State
+from homeassistant.helpers.json import JsonValueType, json_loads
 from homeassistant.setup import async_setup_component
 
 from .test_common import (
@@ -154,13 +154,13 @@ def light_platform_only():
 class JsonValidator:
     """Helper to compare JSON."""
 
-    def __init__(self, jsondata):
+    def __init__(self, jsondata: JsonValueType) -> None:
         """Initialize JSON validator."""
         self.jsondata = jsondata
 
-    def __eq__(self, other):
+    def __eq__(self, other: JsonValueType) -> bool:
         """Compare JSON data."""
-        return json.loads(self.jsondata) == json.loads(other)
+        return json_loads(self.jsondata) == json_loads(other)
 
 
 async def test_fail_setup_if_no_command_topic(
diff --git a/tests/components/mqtt/test_mixins.py b/tests/components/mqtt/test_mixins.py
index 834032a88a0..c9bcd07f26c 100644
--- a/tests/components/mqtt/test_mixins.py
+++ b/tests/components/mqtt/test_mixins.py
@@ -44,7 +44,7 @@ async def test_availability_with_shared_state_topic(
     events = []
 
     @callback
-    def test_callback(event):
+    def test_callback(event) -> None:
         events.append(event)
 
     hass.bus.async_listen(EVENT_STATE_CHANGED, test_callback)
diff --git a/tests/components/mqtt/test_siren.py b/tests/components/mqtt/test_siren.py
index 5af903ec046..d3185a12104 100644
--- a/tests/components/mqtt/test_siren.py
+++ b/tests/components/mqtt/test_siren.py
@@ -1,6 +1,7 @@
 """The tests for the MQTT siren platform."""
 import copy
 from pathlib import Path
+from typing import Any
 from unittest.mock import patch
 
 import pytest
@@ -66,7 +67,11 @@ def siren_platform_only():
         yield
 
 
-async def async_turn_on(hass, entity_id=ENTITY_MATCH_ALL, parameters={}) -> None:
+async def async_turn_on(
+    hass: HomeAssistant,
+    entity_id: str = ENTITY_MATCH_ALL,
+    parameters: dict[str, Any] = {},
+) -> None:
     """Turn all or specified siren on."""
     data = {ATTR_ENTITY_ID: entity_id} if entity_id else {}
     data.update(parameters)
@@ -74,7 +79,9 @@ async def async_turn_on(hass, entity_id=ENTITY_MATCH_ALL, parameters={}) -> None
     await hass.services.async_call(siren.DOMAIN, SERVICE_TURN_ON, data, blocking=True)
 
 
-async def async_turn_off(hass, entity_id=ENTITY_MATCH_ALL) -> None:
+async def async_turn_off(
+    hass: HomeAssistant, entity_id: str = ENTITY_MATCH_ALL
+) -> None:
     """Turn all or specified siren off."""
     data = {ATTR_ENTITY_ID: entity_id} if entity_id else {}