diff --git a/homeassistant/components/homekit/type_security_systems.py b/homeassistant/components/homekit/type_security_systems.py
index 968e60f2842..e32860d1fef 100644
--- a/homeassistant/components/homekit/type_security_systems.py
+++ b/homeassistant/components/homekit/type_security_systems.py
@@ -6,7 +6,7 @@ from pyhap.const import CATEGORY_ALARM_SYSTEM
 from homeassistant.const import (
     STATE_ALARM_ARMED_AWAY, STATE_ALARM_ARMED_HOME,
     STATE_ALARM_ARMED_NIGHT, STATE_ALARM_DISARMED,
-    ATTR_ENTITY_ID, ATTR_CODE)
+    STATE_ALARM_TRIGGERED, ATTR_ENTITY_ID, ATTR_CODE)
 
 from . import TYPES
 from .accessories import HomeAccessory
@@ -16,13 +16,16 @@ from .const import (
 
 _LOGGER = logging.getLogger(__name__)
 
-HASS_TO_HOMEKIT = {STATE_ALARM_DISARMED: 3, STATE_ALARM_ARMED_HOME: 0,
-                   STATE_ALARM_ARMED_AWAY: 1, STATE_ALARM_ARMED_NIGHT: 2}
+HASS_TO_HOMEKIT = {STATE_ALARM_ARMED_HOME: 0,
+                   STATE_ALARM_ARMED_AWAY: 1,
+                   STATE_ALARM_ARMED_NIGHT: 2,
+                   STATE_ALARM_DISARMED: 3,
+                   STATE_ALARM_TRIGGERED: 4}
 HOMEKIT_TO_HASS = {c: s for s, c in HASS_TO_HOMEKIT.items()}
-STATE_TO_SERVICE = {STATE_ALARM_DISARMED: 'alarm_disarm',
-                    STATE_ALARM_ARMED_HOME: 'alarm_arm_home',
+STATE_TO_SERVICE = {STATE_ALARM_ARMED_HOME: 'alarm_arm_home',
                     STATE_ALARM_ARMED_AWAY: 'alarm_arm_away',
-                    STATE_ALARM_ARMED_NIGHT: 'alarm_arm_night'}
+                    STATE_ALARM_ARMED_NIGHT: 'alarm_arm_night',
+                    STATE_ALARM_DISARMED: 'alarm_disarm'}
 
 
 @TYPES.register('SecuritySystem')
@@ -64,7 +67,8 @@ class SecuritySystem(HomeAccessory):
             _LOGGER.debug('%s: Updated current state to %s (%d)',
                           self.entity_id, hass_state, current_security_state)
 
-            if not self.flag_target_state:
+            # SecuritySystemTargetSTate does not support triggered
+            if not self.flag_target_state and \
+                    hass_state != STATE_ALARM_TRIGGERED:
                 self.char_target_state.set_value(current_security_state)
-            if self.char_target_state.value == self.char_current_state.value:
-                self.flag_target_state = False
+            self.flag_target_state = False
diff --git a/tests/components/homekit/test_type_security_systems.py b/tests/components/homekit/test_type_security_systems.py
index 9c1ff0faf1a..baa461af772 100644
--- a/tests/components/homekit/test_type_security_systems.py
+++ b/tests/components/homekit/test_type_security_systems.py
@@ -7,7 +7,8 @@ from homeassistant.components.homekit.type_security_systems import (
 from homeassistant.const import (
     ATTR_CODE, ATTR_SERVICE, ATTR_SERVICE_DATA, EVENT_CALL_SERVICE,
     STATE_ALARM_ARMED_AWAY, STATE_ALARM_ARMED_HOME,
-    STATE_ALARM_ARMED_NIGHT, STATE_ALARM_DISARMED, STATE_UNKNOWN)
+    STATE_ALARM_ARMED_NIGHT, STATE_ALARM_DISARMED, STATE_ALARM_TRIGGERED,
+    STATE_UNKNOWN)
 
 from tests.common import get_test_home_assistant
 
@@ -65,10 +66,15 @@ class TestHomekitSecuritySystems(unittest.TestCase):
         self.assertEqual(acc.char_target_state.value, 3)
         self.assertEqual(acc.char_current_state.value, 3)
 
+        self.hass.states.set(acp, STATE_ALARM_TRIGGERED)
+        self.hass.block_till_done()
+        self.assertEqual(acc.char_target_state.value, 3)
+        self.assertEqual(acc.char_current_state.value, 4)
+
         self.hass.states.set(acp, STATE_UNKNOWN)
         self.hass.block_till_done()
         self.assertEqual(acc.char_target_state.value, 3)
-        self.assertEqual(acc.char_current_state.value, 3)
+        self.assertEqual(acc.char_current_state.value, 4)
 
         # Set from HomeKit
         acc.char_target_state.client_update_value(0)