diff --git a/homeassistant/components/sensor/bom.py b/homeassistant/components/sensor/bom.py
index eb1fddeb810..a49ac48ba6f 100644
--- a/homeassistant/components/sensor/bom.py
+++ b/homeassistant/components/sensor/bom.py
@@ -11,16 +11,17 @@ import requests
 import voluptuous as vol
 
 from homeassistant.components.sensor import PLATFORM_SCHEMA
-from homeassistant.helpers.entity import Entity
-import homeassistant.helpers.config_validation as cv
-from homeassistant.util import Throttle
 from homeassistant.const import (
-    CONF_MONITORED_CONDITIONS, TEMP_CELSIUS,
-    STATE_UNKNOWN, CONF_NAME)
+    CONF_MONITORED_CONDITIONS, TEMP_CELSIUS, STATE_UNKNOWN, CONF_NAME,
+    ATTR_ATTRIBUTION)
+from homeassistant.helpers.entity import Entity
+from homeassistant.util import Throttle
+import homeassistant.helpers.config_validation as cv
 
 _RESOURCE = 'http://www.bom.gov.au/fwo/{}/{}.{}.json'
 _LOGGER = logging.getLogger(__name__)
 
+CONF_ATTRIBUTION = "Data provided by the Australian Bureau of Meteorology"
 CONF_ZONE_ID = 'zone_id'
 CONF_WMO_ID = 'wmo_id'
 
@@ -75,7 +76,7 @@ PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
 
 
 def setup_platform(hass, config, add_devices, discovery_info=None):
-    """Setup the BOM sensor."""
+    """Set up the BOM sensor."""
     rest = BOMCurrentData(
         hass, config.get(CONF_ZONE_ID), config.get(CONF_WMO_ID))
 
@@ -96,7 +97,7 @@ def setup_platform(hass, config, add_devices, discovery_info=None):
 
 
 class BOMCurrentSensor(Entity):
-    """Implementing the BOM current sensor."""
+    """Implementation of a BOM current sensor."""
 
     def __init__(self, rest, condition, stationname):
         """Initialize the sensor."""
@@ -131,6 +132,7 @@ class BOMCurrentSensor(Entity):
         attr['Station Name'] = self.rest.data['name']
         attr['Last Update'] = datetime.datetime.strptime(str(
             self.rest.data['local_date_time_full']), '%Y%m%d%H%M%S')
+        attr[ATTR_ATTRIBUTION] = CONF_ATTRIBUTION
         return attr
 
     @property
diff --git a/homeassistant/components/sensor/coinmarketcap.py b/homeassistant/components/sensor/coinmarketcap.py
index 83adcac7fea..a166ec91d10 100644
--- a/homeassistant/components/sensor/coinmarketcap.py
+++ b/homeassistant/components/sensor/coinmarketcap.py
@@ -12,9 +12,10 @@ from urllib.error import HTTPError
 import voluptuous as vol
 
 from homeassistant.components.sensor import PLATFORM_SCHEMA
-import homeassistant.helpers.config_validation as cv
+from homeassistant.const import ATTR_ATTRIBUTION
 from homeassistant.helpers.entity import Entity
 from homeassistant.util import Throttle
+import homeassistant.helpers.config_validation as cv
 
 REQUIREMENTS = ['coinmarketcap==2.0.1']
 
@@ -30,6 +31,7 @@ ATTR_PRICE = 'price_usd'
 ATTR_SYMBOL = 'symbol'
 ATTR_TOTAL_SUPPLY = 'total_supply'
 
+CONF_ATTRIBUTION = "Data provided by CoinMarketCap"
 CONF_CURRENCY = 'currency'
 
 DEFAULT_CURRENCY = 'bitcoin'
@@ -89,7 +91,7 @@ class CoinMarketCapSensor(Entity):
         return ICON
 
     @property
-    def state_attributes(self):
+    def device_state_attributes(self):
         """Return the state attributes of the sensor."""
         return {
             ATTR_24H_VOLUME_USD: self._ticker.get('24h_volume_usd'),
@@ -99,6 +101,7 @@ class CoinMarketCapSensor(Entity):
             ATTR_PERCENT_CHANGE_7D: self._ticker.get('percent_change_7d'),
             ATTR_SYMBOL: self._ticker.get('symbol'),
             ATTR_TOTAL_SUPPLY: self._ticker.get('total_supply'),
+            ATTR_ATTRIBUTION: CONF_ATTRIBUTION,
         }
 
     # pylint: disable=too-many-branches
diff --git a/homeassistant/components/sensor/darksky.py b/homeassistant/components/sensor/darksky.py
index 241ab5f4655..f092959ba1d 100644
--- a/homeassistant/components/sensor/darksky.py
+++ b/homeassistant/components/sensor/darksky.py
@@ -13,7 +13,7 @@ from requests.exceptions import ConnectionError as ConnectError, \
 
 from homeassistant.components.sensor import PLATFORM_SCHEMA
 from homeassistant.const import (
-    CONF_API_KEY, CONF_NAME, CONF_MONITORED_CONDITIONS)
+    CONF_API_KEY, CONF_NAME, CONF_MONITORED_CONDITIONS, ATTR_ATTRIBUTION)
 from homeassistant.helpers.entity import Entity
 from homeassistant.util import Throttle
 import homeassistant.helpers.config_validation as cv
@@ -22,6 +22,7 @@ REQUIREMENTS = ['python-forecastio==1.3.5']
 
 _LOGGER = logging.getLogger(__name__)
 
+CONF_ATTRIBUTION = "Powered by Dark Sky"
 CONF_UNITS = 'units'
 CONF_UPDATE_INTERVAL = 'update_interval'
 
@@ -178,6 +179,13 @@ class DarkSkySensor(Entity):
         """Icon to use in the frontend, if any."""
         return SENSOR_TYPES[self.type][6]
 
+    @property
+    def device_state_attributes(self):
+        """Return the state attributes."""
+        return {
+            ATTR_ATTRIBUTION: CONF_ATTRIBUTION,
+        }
+
     # pylint: disable=too-many-branches,too-many-statements
     def update(self):
         """Get the latest data from Dark Sky and updates the states."""
diff --git a/homeassistant/components/sensor/fixer.py b/homeassistant/components/sensor/fixer.py
index 8aa5002fbfa..c8fe3b06c4e 100644
--- a/homeassistant/components/sensor/fixer.py
+++ b/homeassistant/components/sensor/fixer.py
@@ -10,7 +10,7 @@ from datetime import timedelta
 import voluptuous as vol
 
 from homeassistant.components.sensor import PLATFORM_SCHEMA
-from homeassistant.const import CONF_NAME
+from homeassistant.const import CONF_NAME, ATTR_ATTRIBUTION
 from homeassistant.helpers.entity import Entity
 from homeassistant.util import Throttle
 import homeassistant.helpers.config_validation as cv
@@ -19,6 +19,11 @@ REQUIREMENTS = ['fixerio==0.1.1']
 
 _LOGGER = logging.getLogger(__name__)
 
+ATTR_BASE = 'Base currency'
+ATTR_EXCHANGE_RATE = 'Exchange rate'
+ATTR_TARGET = 'Target currency'
+
+CONF_ATTRIBUTION = "Data provided by the European Central Bank (ECB)"
 CONF_BASE = 'base'
 CONF_TARGET = 'target'
 
@@ -29,10 +34,6 @@ ICON = 'mdi:currency'
 
 MIN_TIME_BETWEEN_UPDATES = timedelta(days=1)
 
-STATE_ATTR_BASE = 'Base currency'
-STATE_ATTR_EXCHANGE_RATE = 'Exchange rate'
-STATE_ATTR_TARGET = 'Target currency'
-
 PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
     vol.Required(CONF_TARGET): cv.string,
     vol.Optional(CONF_BASE, default=DEFAULT_BASE): cv.string,
@@ -90,9 +91,10 @@ class ExchangeRateSensor(Entity):
         """Return the state attributes."""
         if self.data.rate is not None:
             return {
-                STATE_ATTR_BASE: self.data.rate['base'],
-                STATE_ATTR_TARGET: self._target,
-                STATE_ATTR_EXCHANGE_RATE: self.data.rate['rates'][self._target]
+                ATTR_BASE: self.data.rate['base'],
+                ATTR_TARGET: self._target,
+                ATTR_EXCHANGE_RATE: self.data.rate['rates'][self._target],
+                ATTR_ATTRIBUTION: CONF_ATTRIBUTION,
             }
 
     @property
diff --git a/homeassistant/components/sensor/openweathermap.py b/homeassistant/components/sensor/openweathermap.py
index 9dcb354a125..b59bfa7dab5 100644
--- a/homeassistant/components/sensor/openweathermap.py
+++ b/homeassistant/components/sensor/openweathermap.py
@@ -12,7 +12,7 @@ import voluptuous as vol
 from homeassistant.components.sensor import PLATFORM_SCHEMA
 from homeassistant.const import (
     CONF_API_KEY, CONF_NAME, TEMP_CELSIUS, TEMP_FAHRENHEIT,
-    CONF_MONITORED_CONDITIONS)
+    CONF_MONITORED_CONDITIONS, ATTR_ATTRIBUTION)
 import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.entity import Entity
 from homeassistant.util import Throttle
@@ -21,6 +21,7 @@ REQUIREMENTS = ['pyowm==2.5.0']
 
 _LOGGER = logging.getLogger(__name__)
 
+CONF_ATTRIBUTION = "Data provied by OpenWeatherMap"
 CONF_FORECAST = 'forecast'
 
 DEFAULT_NAME = 'OWM'
@@ -113,6 +114,13 @@ class OpenWeatherMapSensor(Entity):
         """Return the unit of measurement of this entity, if any."""
         return self._unit_of_measurement
 
+    @property
+    def device_state_attributes(self):
+        """Return the state attributes."""
+        return {
+            ATTR_ATTRIBUTION: CONF_ATTRIBUTION,
+        }
+
     # pylint: disable=too-many-branches
     def update(self):
         """Get the latest data from OWM and updates the states."""
diff --git a/homeassistant/components/sensor/swiss_hydrological_data.py b/homeassistant/components/sensor/swiss_hydrological_data.py
index b2e95690727..c8e0be68062 100644
--- a/homeassistant/components/sensor/swiss_hydrological_data.py
+++ b/homeassistant/components/sensor/swiss_hydrological_data.py
@@ -11,7 +11,8 @@ import voluptuous as vol
 import requests
 
 from homeassistant.components.sensor import PLATFORM_SCHEMA
-from homeassistant.const import (TEMP_CELSIUS, CONF_NAME, STATE_UNKNOWN)
+from homeassistant.const import (
+    TEMP_CELSIUS, CONF_NAME, STATE_UNKNOWN, ATTR_ATTRIBUTION)
 import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.entity import Entity
 from homeassistant.util import Throttle
@@ -22,19 +23,23 @@ _LOGGER = logging.getLogger(__name__)
 _RESOURCE = 'http://www.hydrodata.ch/xml/SMS.xml'
 
 CONF_STATION = 'station'
+CONF_ATTRIBUTION = "Data provided by the Swiss Federal Office for the " \
+                   "Environment FOEN"
+
 DEFAULT_NAME = 'Water temperature'
+
 ICON = 'mdi:cup-water'
 
-ATTR_LOCATION = 'Location'
-ATTR_UPDATE = 'Update'
-ATTR_DISCHARGE = 'Discharge'
-ATTR_WATERLEVEL = 'Level'
-ATTR_DISCHARGE_MEAN = 'Discharge mean'
-ATTR_WATERLEVEL_MEAN = 'Level mean'
-ATTR_TEMPERATURE_MEAN = 'Temperature mean'
-ATTR_DISCHARGE_MAX = 'Discharge max'
-ATTR_WATERLEVEL_MAX = 'Level max'
-ATTR_TEMPERATURE_MAX = 'Temperature max'
+ATTR_LOCATION = 'location'
+ATTR_UPDATE = 'update'
+ATTR_DISCHARGE = 'discharge'
+ATTR_WATERLEVEL = 'level'
+ATTR_DISCHARGE_MEAN = 'discharge_mean'
+ATTR_WATERLEVEL_MEAN = 'level_mean'
+ATTR_TEMPERATURE_MEAN = 'temperature_mean'
+ATTR_DISCHARGE_MAX = 'discharge_max'
+ATTR_WATERLEVEL_MAX = 'level_max'
+ATTR_TEMPERATURE_MAX = 'temperature_max'
 
 PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
     vol.Required(CONF_STATION): vol.Coerce(int),
@@ -125,6 +130,7 @@ class SwissHydrologicalDataSensor(Entity):
 
             attributes[ATTR_LOCATION] = self.data.measurings['location']
             attributes[ATTR_UPDATE] = self.data.measurings['update_time']
+            attributes[ATTR_ATTRIBUTION] = CONF_ATTRIBUTION
             return attributes
 
     @property
diff --git a/homeassistant/components/sensor/swiss_public_transport.py b/homeassistant/components/sensor/swiss_public_transport.py
index d7d80ac2a3c..823a96cc01f 100644
--- a/homeassistant/components/sensor/swiss_public_transport.py
+++ b/homeassistant/components/sensor/swiss_public_transport.py
@@ -11,7 +11,7 @@ import requests
 import voluptuous as vol
 
 from homeassistant.components.sensor import PLATFORM_SCHEMA
-from homeassistant.const import CONF_NAME
+from homeassistant.const import CONF_NAME, ATTR_ATTRIBUTION
 import homeassistant.util.dt as dt_util
 from homeassistant.helpers.entity import Entity
 from homeassistant.util import Throttle
@@ -20,12 +20,13 @@ import homeassistant.helpers.config_validation as cv
 _LOGGER = logging.getLogger(__name__)
 _RESOURCE = 'http://transport.opendata.ch/v1/'
 
-ATTR_DEPARTURE_TIME1 = 'Next departure'
-ATTR_DEPARTURE_TIME2 = 'Next on departure'
-ATTR_REMAINING_TIME = 'Remaining time'
-ATTR_START = 'Start'
-ATTR_TARGET = 'Destination'
+ATTR_DEPARTURE_TIME1 = 'next_departure'
+ATTR_DEPARTURE_TIME2 = 'next_on_departure'
+ATTR_REMAINING_TIME = 'remaining_time'
+ATTR_START = 'start'
+ATTR_TARGET = 'destination'
 
+CONF_ATTRIBUTION = "Data provided by transport.opendata.ch"
 CONF_DESTINATION = 'to'
 CONF_START = 'from'
 
@@ -96,7 +97,8 @@ class SwissPublicTransportSensor(Entity):
                 ATTR_START: self._from,
                 ATTR_TARGET: self._to,
                 ATTR_REMAINING_TIME: '{}'.format(
-                    ':'.join(str(self._times[2]).split(':')[:2]))
+                    ':'.join(str(self._times[2]).split(':')[:2])),
+                ATTR_ATTRIBUTION: CONF_ATTRIBUTION,
             }
 
     @property
diff --git a/homeassistant/components/sensor/wunderground.py b/homeassistant/components/sensor/wunderground.py
index 623016518ac..ef20e3f2679 100644
--- a/homeassistant/components/sensor/wunderground.py
+++ b/homeassistant/components/sensor/wunderground.py
@@ -11,16 +11,17 @@ import requests
 import voluptuous as vol
 
 from homeassistant.components.sensor import PLATFORM_SCHEMA
-from homeassistant.helpers.entity import Entity
-import homeassistant.helpers.config_validation as cv
-from homeassistant.util import Throttle
 from homeassistant.const import (
     CONF_MONITORED_CONDITIONS, CONF_API_KEY, TEMP_FAHRENHEIT, TEMP_CELSIUS,
-    STATE_UNKNOWN)
+    STATE_UNKNOWN, ATTR_ATTRIBUTION)
+from homeassistant.helpers.entity import Entity
+from homeassistant.util import Throttle
+import homeassistant.helpers.config_validation as cv
 
 _RESOURCE = 'http://api.wunderground.com/api/{}/conditions/q/'
 _LOGGER = logging.getLogger(__name__)
 
+CONF_ATTRIBUTION = "Data provided by the WUnderground weather service"
 CONF_PWS_ID = 'pws_id'
 
 MIN_TIME_BETWEEN_UPDATES = timedelta(seconds=300)
@@ -108,6 +109,13 @@ class WUndergroundSensor(Entity):
         else:
             return STATE_UNKNOWN
 
+    @property
+    def device_state_attributes(self):
+        """Return the state attributes."""
+        return {
+            ATTR_ATTRIBUTION: CONF_ATTRIBUTION,
+        }
+
     @property
     def entity_picture(self):
         """Return the entity picture."""
@@ -123,9 +131,8 @@ class WUndergroundSensor(Entity):
         """Update current conditions."""
         self.rest.update()
 
+
 # pylint: disable=too-few-public-methods
-
-
 class WUndergroundData(object):
     """Get data from WUnderground."""
 
diff --git a/homeassistant/components/sensor/yahoo_finance.py b/homeassistant/components/sensor/yahoo_finance.py
index 822c50823fc..a389a13656d 100644
--- a/homeassistant/components/sensor/yahoo_finance.py
+++ b/homeassistant/components/sensor/yahoo_finance.py
@@ -10,7 +10,7 @@ from datetime import timedelta
 import voluptuous as vol
 
 from homeassistant.components.sensor import PLATFORM_SCHEMA
-from homeassistant.const import CONF_NAME
+from homeassistant.const import CONF_NAME, ATTR_ATTRIBUTION
 from homeassistant.helpers.entity import Entity
 from homeassistant.util import Throttle
 import homeassistant.helpers.config_validation as cv
@@ -19,7 +19,9 @@ REQUIREMENTS = ['yahoo-finance==1.2.1']
 
 _LOGGER = logging.getLogger(__name__)
 
+CONF_ATTRIBUTION = "Stock market information provided by Yahoo! Inc."
 CONF_SYMBOL = 'symbol'
+
 DEFAULT_SYMBOL = 'YHOO'
 DEFAULT_NAME = 'Yahoo Stock'
 
@@ -28,8 +30,8 @@ ICON = 'mdi:currency-usd'
 MIN_TIME_BETWEEN_UPDATES = timedelta(minutes=1)
 
 ATTR_CHANGE = 'Change'
-ATTR_OPEN = 'Open'
-ATTR_PREV_CLOSE = 'Prev. Close'
+ATTR_OPEN = 'open'
+ATTR_PREV_CLOSE = 'prev_close'
 
 PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
     vol.Optional(CONF_SYMBOL, default=DEFAULT_SYMBOL): cv.string,
@@ -82,10 +84,7 @@ class YahooFinanceSensor(Entity):
                 ATTR_CHANGE: self.data.price_change,
                 ATTR_OPEN: self.data.price_open,
                 ATTR_PREV_CLOSE: self.data.prev_close,
-                'About': "Stock market information delivered by Yahoo!"
-                         " Inc. are provided free of charge for use"
-                         " by individuals and non-profit organizations"
-                         " for personal, non-commercial uses."
+                ATTR_ATTRIBUTION: CONF_ATTRIBUTION,
             }
 
     @property
diff --git a/homeassistant/components/sensor/yr.py b/homeassistant/components/sensor/yr.py
index d69bd65688a..be7693f6e4f 100644
--- a/homeassistant/components/sensor/yr.py
+++ b/homeassistant/components/sensor/yr.py
@@ -5,13 +5,15 @@ For more details about this platform, please refer to the documentation at
 https://home-assistant.io/components/sensor.yr/
 """
 import logging
+
 import requests
 import voluptuous as vol
 
 import homeassistant.helpers.config_validation as cv
 from homeassistant.components.sensor import PLATFORM_SCHEMA
 from homeassistant.const import (
-    CONF_LATITUDE, CONF_LONGITUDE, CONF_ELEVATION, CONF_MONITORED_CONDITIONS)
+    CONF_LATITUDE, CONF_LONGITUDE, CONF_ELEVATION, CONF_MONITORED_CONDITIONS,
+    ATTR_ATTRIBUTION)
 from homeassistant.helpers.entity import Entity
 from homeassistant.util import dt as dt_util
 
@@ -19,6 +21,9 @@ REQUIREMENTS = ['xmltodict==0.10.2']
 
 _LOGGER = logging.getLogger(__name__)
 
+CONF_ATTRIBUTION = "Weather forecast from yr.no, delivered by the Norwegian " \
+                   "Meteorological Institute and the NRK."
+
 # Sensor types are defined like so:
 SENSOR_TYPES = {
     'symbol': ['Symbol', None],
@@ -108,8 +113,7 @@ class YrSensor(Entity):
     def device_state_attributes(self):
         """Return the state attributes."""
         return {
-            'about': "Weather forecast from yr.no, delivered by the"
-                     " Norwegian Meteorological Institute and the NRK"
+            ATTR_ATTRIBUTION: CONF_ATTRIBUTION,
         }
 
     @property
diff --git a/homeassistant/components/sensor/yweather.py b/homeassistant/components/sensor/yweather.py
index f482d8d2e2c..f59913facb8 100644
--- a/homeassistant/components/sensor/yweather.py
+++ b/homeassistant/components/sensor/yweather.py
@@ -11,7 +11,8 @@ import voluptuous as vol
 
 from homeassistant.components.sensor import PLATFORM_SCHEMA
 from homeassistant.const import (
-    TEMP_CELSIUS, CONF_MONITORED_CONDITIONS, CONF_NAME, STATE_UNKNOWN)
+    TEMP_CELSIUS, CONF_MONITORED_CONDITIONS, CONF_NAME, STATE_UNKNOWN,
+    ATTR_ATTRIBUTION)
 import homeassistant.helpers.config_validation as cv
 from homeassistant.helpers.entity import Entity
 from homeassistant.util import Throttle
@@ -20,6 +21,7 @@ REQUIREMENTS = ["yahooweather==0.8"]
 
 _LOGGER = logging.getLogger(__name__)
 
+CONF_ATTRIBUTION = "Weather details provided by Yahoo! Inc."
 CONF_FORECAST = 'forecast'
 CONF_WOEID = 'woeid'
 
@@ -140,9 +142,7 @@ class YahooWeatherSensor(Entity):
     def device_state_attributes(self):
         """Return the state attributes."""
         return {
-            'about': "Weather forecast delivered by Yahoo! Inc. are provided"
-                     " free of charge for use by individuals and non-profit"
-                     " organizations for personal, non-commercial uses."
+            ATTR_ATTRIBUTION: CONF_ATTRIBUTION,
         }
 
     def update(self):
diff --git a/homeassistant/const.py b/homeassistant/const.py
index 6203d99ec20..e2670d2b08f 100644
--- a/homeassistant/const.py
+++ b/homeassistant/const.py
@@ -173,6 +173,9 @@ STATE_UNLOCKED = 'unlocked'
 STATE_UNAVAILABLE = 'unavailable'
 
 # #### STATE AND EVENT ATTRIBUTES ####
+# Attribution
+ATTR_ATTRIBUTION = 'attribution'
+
 # Contains current time for a TIME_CHANGED event
 ATTR_NOW = 'now'