diff --git a/homeassistant/components/device_sun_light_trigger.py b/homeassistant/components/device_sun_light_trigger.py
index ed31e624b913..9da4348362d4 100644
--- a/homeassistant/components/device_sun_light_trigger.py
+++ b/homeassistant/components/device_sun_light_trigger.py
@@ -9,6 +9,7 @@ from datetime import timedelta
 
 import voluptuous as vol
 
+from homeassistant.core import callback
 import homeassistant.util.dt as dt_util
 from homeassistant.const import STATE_HOME, STATE_NOT_HOME
 from homeassistant.helpers.event import track_point_in_time
@@ -79,21 +80,22 @@ def setup(hass, config):
             return None
         return next_setting - LIGHT_TRANSITION_TIME * len(light_ids)
 
-    def turn_light_on_before_sunset(light_id):
+    def async_turn_on_before_sunset(light_id):
         """Helper function to turn on lights.
 
         Speed is slow if there are devices home and the light is not on yet.
         """
         if not device_tracker.is_on(hass) or light.is_on(hass, light_id):
             return
-        light.turn_on(hass, light_id,
-                      transition=LIGHT_TRANSITION_TIME.seconds,
-                      profile=light_profile)
+        light.async_turn_on(hass, light_id,
+                            transition=LIGHT_TRANSITION_TIME.seconds,
+                            profile=light_profile)
 
     # Track every time sun rises so we can schedule a time-based
     # pre-sun set event
     @track_state_change(sun.ENTITY_ID, sun.STATE_BELOW_HORIZON,
                         sun.STATE_ABOVE_HORIZON)
+    @callback
     def schedule_lights_at_sun_set(hass, entity, old_state, new_state):
         """The moment sun sets we want to have all the lights on.
 
@@ -104,16 +106,21 @@ def setup(hass, config):
         if not start_point:
             return
 
-        def turn_on(light_id):
+        def async_turn_on_factory(light_id):
             """Lambda can keep track of function parameters.
 
             No local parameters. If we put the lambda directly in the below
             statement only the last light will be turned on.
             """
-            return lambda now: turn_light_on_before_sunset(light_id)
+            @callback
+            def async_turn_on_light(now):
+                """Turn on specific light."""
+                async_turn_on_before_sunset(light_id)
+
+            return async_turn_on_light
 
         for index, light_id in enumerate(light_ids):
-            track_point_in_time(hass, turn_on(light_id),
+            track_point_in_time(hass, async_turn_on_factory(light_id),
                                 start_point + index * LIGHT_TRANSITION_TIME)
 
     # If the sun is already above horizon schedule the time-based pre-sun set
@@ -122,6 +129,7 @@ def setup(hass, config):
         schedule_lights_at_sun_set(hass, None, None, None)
 
     @track_state_change(device_entity_ids, STATE_NOT_HOME, STATE_HOME)
+    @callback
     def check_light_on_dev_state_change(hass, entity, old_state, new_state):
         """Handle tracked device state changes."""
         # pylint: disable=unused-variable
@@ -136,7 +144,7 @@ def setup(hass, config):
         # Do we need lights?
         if light_needed:
             logger.info("Home coming event for %s. Turning lights on", entity)
-            light.turn_on(hass, light_ids, profile=light_profile)
+            light.async_turn_on(hass, light_ids, profile=light_profile)
 
         # Are we in the time span were we would turn on the lights
         # if someone would be home?
@@ -149,7 +157,7 @@ def setup(hass, config):
             # when the fading in started and turn it on if so
             for index, light_id in enumerate(light_ids):
                 if now > start_point + index * LIGHT_TRANSITION_TIME:
-                    light.turn_on(hass, light_id)
+                    light.async_turn_on(hass, light_id)
 
                 else:
                     # If this light didn't happen to be turned on yet so
@@ -158,6 +166,7 @@ def setup(hass, config):
 
     if not disable_turn_off:
         @track_state_change(device_group, STATE_HOME, STATE_NOT_HOME)
+        @callback
         def turn_off_lights_when_all_leave(hass, entity, old_state, new_state):
             """Handle device group state change."""
             # pylint: disable=unused-variable
@@ -166,6 +175,6 @@ def setup(hass, config):
 
             logger.info(
                 "Everyone has left but there are lights on. Turning them off")
-            light.turn_off(hass, light_ids)
+            light.async_turn_off(hass, light_ids)
 
     return True
diff --git a/homeassistant/components/light/__init__.py b/homeassistant/components/light/__init__.py
index e3437d89e728..b4708164fe2a 100644
--- a/homeassistant/components/light/__init__.py
+++ b/homeassistant/components/light/__init__.py
@@ -10,6 +10,7 @@ import csv
 
 import voluptuous as vol
 
+from homeassistant.core import callback
 from homeassistant.components import group
 from homeassistant.config import load_yaml_config_file
 from homeassistant.const import (
@@ -20,6 +21,7 @@ from homeassistant.helpers.entity_component import EntityComponent
 from homeassistant.helpers.config_validation import PLATFORM_SCHEMA  # noqa
 import homeassistant.helpers.config_validation as cv
 import homeassistant.util.color as color_util
+from homeassistant.util.async import run_callback_threadsafe
 
 
 DOMAIN = "light"
@@ -128,6 +130,18 @@ def turn_on(hass, entity_id=None, transition=None, brightness=None,
             rgb_color=None, xy_color=None, color_temp=None, white_value=None,
             profile=None, flash=None, effect=None, color_name=None):
     """Turn all or specified light on."""
+    run_callback_threadsafe(
+        hass.loop, async_turn_on, hass, entity_id, transition, brightness,
+        rgb_color, xy_color, color_temp, white_value,
+        profile, flash, effect, color_name).result()
+
+
+@callback
+def async_turn_on(hass, entity_id=None, transition=None, brightness=None,
+                  rgb_color=None, xy_color=None, color_temp=None,
+                  white_value=None, profile=None, flash=None, effect=None,
+                  color_name=None):
+    """Turn all or specified light on."""
     data = {
         key: value for key, value in [
             (ATTR_ENTITY_ID, entity_id),
@@ -144,10 +158,17 @@ def turn_on(hass, entity_id=None, transition=None, brightness=None,
         ] if value is not None
     }
 
-    hass.services.call(DOMAIN, SERVICE_TURN_ON, data)
+    hass.async_add_job(hass.services.async_call, DOMAIN, SERVICE_TURN_ON, data)
 
 
 def turn_off(hass, entity_id=None, transition=None):
+    """Turn all or specified light off."""
+    run_callback_threadsafe(
+        hass.loop, async_turn_off, hass, entity_id, transition).result()
+
+
+@callback
+def async_turn_off(hass, entity_id=None, transition=None):
     """Turn all or specified light off."""
     data = {
         key: value for key, value in [
@@ -156,7 +177,8 @@ def turn_off(hass, entity_id=None, transition=None):
         ] if value is not None
     }
 
-    hass.services.call(DOMAIN, SERVICE_TURN_OFF, data)
+    hass.async_add_job(hass.services.async_call, DOMAIN, SERVICE_TURN_OFF,
+                       data)
 
 
 def toggle(hass, entity_id=None, transition=None):
diff --git a/homeassistant/components/sun.py b/homeassistant/components/sun.py
index 858d49a8e438..20bebe79f9e4 100644
--- a/homeassistant/components/sun.py
+++ b/homeassistant/components/sun.py
@@ -49,14 +49,20 @@ def is_on(hass, entity_id=None):
 
 
 def next_setting(hass, entity_id=None):
-    """Local datetime object of the next sun setting."""
+    """Local datetime object of the next sun setting.
+
+    Async friendly.
+    """
     utc_next = next_setting_utc(hass, entity_id)
 
     return dt_util.as_local(utc_next) if utc_next else None
 
 
 def next_setting_utc(hass, entity_id=None):
-    """UTC datetime object of the next sun setting."""
+    """UTC datetime object of the next sun setting.
+
+    Async friendly.
+    """
     entity_id = entity_id or ENTITY_ID
 
     state = hass.states.get(ENTITY_ID)
@@ -71,14 +77,20 @@ def next_setting_utc(hass, entity_id=None):
 
 
 def next_rising(hass, entity_id=None):
-    """Local datetime object of the next sun rising."""
+    """Local datetime object of the next sun rising.
+
+    Async friendly.
+    """
     utc_next = next_rising_utc(hass, entity_id)
 
     return dt_util.as_local(utc_next) if utc_next else None
 
 
 def next_rising_utc(hass, entity_id=None):
-    """UTC datetime object of the next sun rising."""
+    """UTC datetime object of the next sun rising.
+
+    Async friendly.
+    """
     entity_id = entity_id or ENTITY_ID
 
     state = hass.states.get(ENTITY_ID)
diff --git a/tests/common.py b/tests/common.py
index fd72a6b635b9..6f017d29b46f 100644
--- a/tests/common.py
+++ b/tests/common.py
@@ -129,8 +129,12 @@ def mock_service(hass, domain, service):
     """
     calls = []
 
+    @ha.callback
+    def mock_service(call):
+        calls.append(call)
+
     # pylint: disable=unnecessary-lambda
-    hass.services.register(domain, service, lambda call: calls.append(call))
+    hass.services.register(domain, service, mock_service)
 
     return calls
 
diff --git a/tests/components/automation/test_event.py b/tests/components/automation/test_event.py
index 2ab62833edaf..22158402ff91 100644
--- a/tests/components/automation/test_event.py
+++ b/tests/components/automation/test_event.py
@@ -1,6 +1,7 @@
 """The tests for the Event automation."""
 import unittest
 
+from homeassistant.core import callback
 from homeassistant.bootstrap import setup_component
 import homeassistant.components.automation as automation
 
@@ -16,6 +17,7 @@ class TestAutomationEvent(unittest.TestCase):
         self.hass.config.components.append('group')
         self.calls = []
 
+        @callback
         def record_call(service):
             """Helper for recording the call."""
             self.calls.append(service)
diff --git a/tests/components/automation/test_init.py b/tests/components/automation/test_init.py
index 2956be98b00e..2459542b629a 100644
--- a/tests/components/automation/test_init.py
+++ b/tests/components/automation/test_init.py
@@ -2,6 +2,7 @@
 import unittest
 from unittest.mock import patch
 
+from homeassistant.core import callback
 from homeassistant.bootstrap import setup_component
 import homeassistant.components.automation as automation
 from homeassistant.const import ATTR_ENTITY_ID
@@ -22,6 +23,7 @@ class TestAutomation(unittest.TestCase):
         self.hass.config.components.append('group')
         self.calls = []
 
+        @callback
         def record_call(service):
             """Record call."""
             self.calls.append(service)
diff --git a/tests/components/automation/test_mqtt.py b/tests/components/automation/test_mqtt.py
index b7da76fda206..4e58dc7a442d 100644
--- a/tests/components/automation/test_mqtt.py
+++ b/tests/components/automation/test_mqtt.py
@@ -1,6 +1,7 @@
 """The tests for the MQTT automation."""
 import unittest
 
+from homeassistant.core import callback
 from homeassistant.bootstrap import setup_component
 import homeassistant.components.automation as automation
 from tests.common import (
@@ -17,6 +18,7 @@ class TestAutomationMQTT(unittest.TestCase):
         mock_mqtt_component(self.hass)
         self.calls = []
 
+        @callback
         def record_call(service):
             self.calls.append(service)
 
diff --git a/tests/components/automation/test_numeric_state.py b/tests/components/automation/test_numeric_state.py
index fa2d237ee00c..d0aedd87f466 100644
--- a/tests/components/automation/test_numeric_state.py
+++ b/tests/components/automation/test_numeric_state.py
@@ -1,6 +1,7 @@
 """The tests for numeric state automation."""
 import unittest
 
+from homeassistant.core import callback
 from homeassistant.bootstrap import setup_component
 import homeassistant.components.automation as automation
 
@@ -16,6 +17,7 @@ class TestAutomationNumericState(unittest.TestCase):
         self.hass.config.components.append('group')
         self.calls = []
 
+        @callback
         def record_call(service):
             """Helper to record calls."""
             self.calls.append(service)
diff --git a/tests/components/automation/test_state.py b/tests/components/automation/test_state.py
index 06c127ca6b72..3b4e44861129 100644
--- a/tests/components/automation/test_state.py
+++ b/tests/components/automation/test_state.py
@@ -3,6 +3,7 @@ import unittest
 from datetime import timedelta
 from unittest.mock import patch
 
+from homeassistant.core import callback
 from homeassistant.bootstrap import setup_component
 import homeassistant.util.dt as dt_util
 import homeassistant.components.automation as automation
@@ -21,6 +22,7 @@ class TestAutomationState(unittest.TestCase):
         self.hass.states.set('test.entity', 'hello')
         self.calls = []
 
+        @callback
         def record_call(service):
             self.calls.append(service)
 
diff --git a/tests/components/automation/test_sun.py b/tests/components/automation/test_sun.py
index ca3d1618013f..475a8f552595 100644
--- a/tests/components/automation/test_sun.py
+++ b/tests/components/automation/test_sun.py
@@ -3,6 +3,7 @@ from datetime import datetime
 import unittest
 from unittest.mock import patch
 
+from homeassistant.core import callback
 from homeassistant.bootstrap import setup_component
 from homeassistant.components import sun
 import homeassistant.components.automation as automation
@@ -22,6 +23,7 @@ class TestAutomationSun(unittest.TestCase):
 
         self.calls = []
 
+        @callback
         def record_call(service):
             self.calls.append(service)
 
diff --git a/tests/components/automation/test_template.py b/tests/components/automation/test_template.py
index fcd1a48983a9..1430d303140f 100644
--- a/tests/components/automation/test_template.py
+++ b/tests/components/automation/test_template.py
@@ -1,6 +1,7 @@
 """The tests for the Template automation."""
 import unittest
 
+from homeassistant.core import callback
 from homeassistant.bootstrap import setup_component
 import homeassistant.components.automation as automation
 
@@ -17,6 +18,7 @@ class TestAutomationTemplate(unittest.TestCase):
         self.hass.states.set('test.entity', 'hello')
         self.calls = []
 
+        @callback
         def record_call(service):
             """helper for recording calls."""
             self.calls.append(service)
diff --git a/tests/components/automation/test_time.py b/tests/components/automation/test_time.py
index dba100aa345f..ff2d20145d94 100644
--- a/tests/components/automation/test_time.py
+++ b/tests/components/automation/test_time.py
@@ -3,6 +3,7 @@ from datetime import timedelta
 import unittest
 from unittest.mock import patch
 
+from homeassistant.core import callback
 from homeassistant.bootstrap import setup_component
 import homeassistant.util.dt as dt_util
 import homeassistant.components.automation as automation
@@ -20,6 +21,7 @@ class TestAutomationTime(unittest.TestCase):
         self.hass.config.components.append('group')
         self.calls = []
 
+        @callback
         def record_call(service):
             self.calls.append(service)
 
diff --git a/tests/components/automation/test_zone.py b/tests/components/automation/test_zone.py
index e454b8b5b8bf..d81cb8f0bd53 100644
--- a/tests/components/automation/test_zone.py
+++ b/tests/components/automation/test_zone.py
@@ -1,6 +1,7 @@
 """The tests for the location automation."""
 import unittest
 
+from homeassistant.core import callback
 from homeassistant.bootstrap import setup_component
 from homeassistant.components import automation, zone
 
@@ -25,6 +26,7 @@ class TestAutomationZone(unittest.TestCase):
 
         self.calls = []
 
+        @callback
         def record_call(service):
             self.calls.append(service)
 
diff --git a/tests/components/climate/test_generic_thermostat.py b/tests/components/climate/test_generic_thermostat.py
index 070ca31f8dfc..d11d925ef41d 100644
--- a/tests/components/climate/test_generic_thermostat.py
+++ b/tests/components/climate/test_generic_thermostat.py
@@ -3,7 +3,7 @@ import datetime
 import unittest
 from unittest import mock
 
-
+from homeassistant.core import callback
 from homeassistant.bootstrap import setup_component
 from homeassistant.const import (
     ATTR_UNIT_OF_MEASUREMENT,
@@ -216,6 +216,7 @@ class TestClimateGenericThermostat(unittest.TestCase):
         self.hass.states.set(ENT_SWITCH, STATE_ON if is_on else STATE_OFF)
         self.calls = []
 
+        @callback
         def log_call(call):
             """Log service calls."""
             self.calls.append(call)
@@ -306,6 +307,7 @@ class TestClimateGenericThermostatACMode(unittest.TestCase):
         self.hass.states.set(ENT_SWITCH, STATE_ON if is_on else STATE_OFF)
         self.calls = []
 
+        @callback
         def log_call(call):
             """Log service calls."""
             self.calls.append(call)
@@ -397,6 +399,7 @@ class TestClimateGenericThermostatACModeMinCycle(unittest.TestCase):
         self.hass.states.set(ENT_SWITCH, STATE_ON if is_on else STATE_OFF)
         self.calls = []
 
+        @callback
         def log_call(call):
             """Log service calls."""
             self.calls.append(call)
@@ -487,6 +490,7 @@ class TestClimateGenericThermostatMinCycle(unittest.TestCase):
         self.hass.states.set(ENT_SWITCH, STATE_ON if is_on else STATE_OFF)
         self.calls = []
 
+        @callback
         def log_call(call):
             """Log service calls."""
             self.calls.append(call)
diff --git a/tests/components/switch/test_template.py b/tests/components/switch/test_template.py
index af91c9a565b0..2f67564e6e85 100644
--- a/tests/components/switch/test_template.py
+++ b/tests/components/switch/test_template.py
@@ -1,7 +1,7 @@
 """The tests for the  Template switch platform."""
+from homeassistant.core import callback
 import homeassistant.bootstrap as bootstrap
 import homeassistant.components as core
-
 from homeassistant.const import (
     STATE_ON,
     STATE_OFF)
@@ -21,6 +21,7 @@ class TestTemplateSwitch:
         self.hass = get_test_home_assistant()
         self.calls = []
 
+        @callback
         def record_call(service):
             """Track function calls.."""
             self.calls.append(service)
diff --git a/tests/components/test_alexa.py b/tests/components/test_alexa.py
index 28a808681633..41e7474974d4 100644
--- a/tests/components/test_alexa.py
+++ b/tests/components/test_alexa.py
@@ -6,6 +6,7 @@ import unittest
 
 import requests
 
+from homeassistant.core import callback
 from homeassistant import bootstrap, const
 from homeassistant.components import alexa, http
 
@@ -47,7 +48,11 @@ def setUpModule():
         {http.DOMAIN: {http.CONF_API_PASSWORD: API_PASSWORD,
                        http.CONF_SERVER_PORT: SERVER_PORT}})
 
-    hass.services.register("test", "alexa", lambda call: calls.append(call))
+    @callback
+    def mock_service(call):
+        calls.append(call)
+
+    hass.services.register("test", "alexa", mock_service)
 
     bootstrap.setup_component(hass, alexa.DOMAIN, {
         # Key is here to verify we allow other keys in config too
diff --git a/tests/components/test_api.py b/tests/components/test_api.py
index a70048956ebd..28ffa7405e74 100644
--- a/tests/components/test_api.py
+++ b/tests/components/test_api.py
@@ -288,6 +288,7 @@ class TestAPI(unittest.TestCase):
         """Test if the API allows us to call a service."""
         test_value = []
 
+        @ha.callback
         def listener(service_call):
             """Helper method that will verify that our service got called."""
             test_value.append(1)
@@ -307,6 +308,7 @@ class TestAPI(unittest.TestCase):
         """Test if the API allows us to call a service."""
         test_value = []
 
+        @ha.callback
         def listener(service_call):
             """Helper method that will verify that our service got called.
 
diff --git a/tests/components/test_conversation.py b/tests/components/test_conversation.py
index 1172221f16ff..919c95be4c54 100644
--- a/tests/components/test_conversation.py
+++ b/tests/components/test_conversation.py
@@ -3,6 +3,7 @@
 import unittest
 from unittest.mock import patch
 
+from homeassistant.core import callback
 from homeassistant.bootstrap import setup_component
 import homeassistant.components as core_components
 from homeassistant.components import conversation
@@ -38,6 +39,7 @@ class TestConversation(unittest.TestCase):
         """Setup and perform good turn on requests."""
         calls = []
 
+        @callback
         def record_call(service):
             calls.append(service)
 
@@ -56,6 +58,7 @@ class TestConversation(unittest.TestCase):
         """Setup and perform good turn off requests."""
         calls = []
 
+        @callback
         def record_call(service):
             calls.append(service)
 
diff --git a/tests/components/test_script.py b/tests/components/test_script.py
index 979e435456ca..76df0a240556 100644
--- a/tests/components/test_script.py
+++ b/tests/components/test_script.py
@@ -130,6 +130,7 @@ class TestScriptComponent(unittest.TestCase):
         """Test different ways of passing in variables."""
         calls = []
 
+        @callback
         def record_call(service):
             """Add recorded event to set."""
             calls.append(service)
diff --git a/tests/test_core.py b/tests/test_core.py
index d3a2d4f353f6..51653500b6e8 100644
--- a/tests/test_core.py
+++ b/tests/test_core.py
@@ -508,7 +508,12 @@ class TestServiceRegistry(unittest.TestCase):
         """Setup things to be run when tests are started."""
         self.hass = get_test_home_assistant()
         self.services = self.hass.services
-        self.services.register("Test_Domain", "TEST_SERVICE", lambda x: None)
+
+        @ha.callback
+        def mock_service(call):
+            pass
+
+        self.services.register("Test_Domain", "TEST_SERVICE", mock_service)
 
     # pylint: disable=invalid-name
     def tearDown(self):
@@ -535,6 +540,7 @@ class TestServiceRegistry(unittest.TestCase):
         """Test call with blocking."""
         calls = []
 
+        @ha.callback
         def service_handler(call):
             """Service handler."""
             calls.append(call)
diff --git a/tests/test_remote.py b/tests/test_remote.py
index 8692fd4a1332..55d8ca18b5fc 100644
--- a/tests/test_remote.py
+++ b/tests/test_remote.py
@@ -116,6 +116,7 @@ class TestRemoteMethods(unittest.TestCase):
         """Test Python API fire_event."""
         test_value = []
 
+        @ha.callback
         def listener(event):
             """Helper method that will verify our event got called."""
             test_value.append(1)
@@ -200,6 +201,7 @@ class TestRemoteMethods(unittest.TestCase):
         """Test Python API services.call."""
         test_value = []
 
+        @ha.callback
         def listener(service_call):
             """Helper method that will verify that our service got called."""
             test_value.append(1)