diff --git a/homeassistant/components/plex/__init__.py b/homeassistant/components/plex/__init__.py
index 7f8caf8390b..cc281ed8147 100644
--- a/homeassistant/components/plex/__init__.py
+++ b/homeassistant/components/plex/__init__.py
@@ -1,6 +1,7 @@
 """Support to embed Plex."""
 import asyncio
 import functools
+import json
 import logging
 
 import plexapi.exceptions
@@ -10,7 +11,12 @@ import voluptuous as vol
 
 from homeassistant import config_entries
 from homeassistant.components.media_player import DOMAIN as MP_DOMAIN
+from homeassistant.components.media_player.const import (
+    ATTR_MEDIA_CONTENT_ID,
+    ATTR_MEDIA_CONTENT_TYPE,
+)
 from homeassistant.const import (
+    ATTR_ENTITY_ID,
     CONF_HOST,
     CONF_PORT,
     CONF_SSL,
@@ -19,7 +25,7 @@ from homeassistant.const import (
     CONF_VERIFY_SSL,
     EVENT_HOMEASSISTANT_STOP,
 )
-from homeassistant.exceptions import ConfigEntryNotReady
+from homeassistant.exceptions import ConfigEntryNotReady, HomeAssistantError
 from homeassistant.helpers import config_validation as cv
 from homeassistant.helpers.aiohttp_client import async_get_clientsession
 from homeassistant.helpers.dispatcher import (
@@ -44,6 +50,7 @@ from .const import (
     PLEX_SERVER_CONFIG,
     PLEX_UPDATE_PLATFORMS_SIGNAL,
     SERVERS,
+    SERVICE_PLAY_ON_SONOS,
     WEBSOCKETS,
 )
 from .errors import ShouldUpdateConfigEntry
@@ -215,6 +222,24 @@ async def async_setup_entry(hass, entry):
         )
         task.add_done_callback(functools.partial(start_websocket_session, platform))
 
+    async def async_play_on_sonos_service(service_call):
+        await hass.async_add_executor_job(play_on_sonos, hass, service_call)
+
+    play_on_sonos_schema = vol.Schema(
+        {
+            vol.Required(ATTR_ENTITY_ID): cv.entity_id,
+            vol.Required(ATTR_MEDIA_CONTENT_ID): str,
+            vol.Optional(ATTR_MEDIA_CONTENT_TYPE): vol.In("music"),
+        }
+    )
+
+    hass.services.async_register(
+        PLEX_DOMAIN,
+        SERVICE_PLAY_ON_SONOS,
+        async_play_on_sonos_service,
+        schema=play_on_sonos_schema,
+    )
+
     return True
 
 
@@ -244,3 +269,52 @@ async def async_options_updated(hass, entry):
     """Triggered by config entry options updates."""
     server_id = entry.data[CONF_SERVER_IDENTIFIER]
     hass.data[PLEX_DOMAIN][SERVERS][server_id].options = entry.options
+
+
+def play_on_sonos(hass, service_call):
+    """Play Plex media on a linked Sonos device."""
+    entity_id = service_call.data[ATTR_ENTITY_ID]
+    content_id = service_call.data[ATTR_MEDIA_CONTENT_ID]
+    content = json.loads(content_id)
+
+    sonos = hass.components.sonos
+    try:
+        sonos_id = sonos.get_coordinator_id(entity_id)
+    except HomeAssistantError as err:
+        _LOGGER.error("Cannot get Sonos device: %s", err)
+        return
+
+    if isinstance(content, int):
+        content = {"plex_key": content}
+
+    plex_server_name = content.get("plex_server")
+    shuffle = content.pop("shuffle", 0)
+
+    plex_servers = hass.data[PLEX_DOMAIN][SERVERS].values()
+    if plex_server_name:
+        plex_server = [x for x in plex_servers if x.friendly_name == plex_server_name]
+        if not plex_server:
+            _LOGGER.error(
+                "Requested Plex server '%s' not found in %s",
+                plex_server_name,
+                list(map(lambda x: x.friendly_name, plex_servers)),
+            )
+            return
+    else:
+        plex_server = next(iter(plex_servers))
+
+    sonos_speaker = plex_server.account.sonos_speaker_by_id(sonos_id)
+    if sonos_speaker is None:
+        _LOGGER.error(
+            "Sonos speaker '%s' could not be found on this Plex account", sonos_id
+        )
+        return
+
+    media = plex_server.lookup_media("music", **content)
+    if media is None:
+        _LOGGER.error("Media could not be found: %s", content)
+        return
+
+    _LOGGER.debug("Attempting to play '%s' on %s", media, sonos_speaker)
+    playqueue = plex_server.create_playqueue(media, shuffle=shuffle)
+    sonos_speaker.playMedia(playqueue)
diff --git a/homeassistant/components/plex/const.py b/homeassistant/components/plex/const.py
index e8bcfb42ca6..d17710c4436 100644
--- a/homeassistant/components/plex/const.py
+++ b/homeassistant/components/plex/const.py
@@ -43,3 +43,5 @@ X_PLEX_VERSION = __version__
 
 AUTOMATIC_SETUP_STRING = "Obtain a new token from plex.tv"
 MANUAL_SETUP_STRING = "Configure Plex server manually"
+
+SERVICE_PLAY_ON_SONOS = "play_on_sonos"
diff --git a/homeassistant/components/plex/manifest.json b/homeassistant/components/plex/manifest.json
index e48a37a77d5..b864cae3557 100644
--- a/homeassistant/components/plex/manifest.json
+++ b/homeassistant/components/plex/manifest.json
@@ -5,5 +5,6 @@
   "documentation": "https://www.home-assistant.io/integrations/plex",
   "requirements": ["plexapi==3.6.0", "plexauth==0.0.5", "plexwebsocket==0.0.8"],
   "dependencies": ["http"],
+  "after_dependencies": ["sonos"],
   "codeowners": ["@jjlawren"]
 }
diff --git a/homeassistant/components/plex/server.py b/homeassistant/components/plex/server.py
index 933a899e3b2..88b4b533f88 100644
--- a/homeassistant/components/plex/server.py
+++ b/homeassistant/components/plex/server.py
@@ -57,6 +57,7 @@ class PlexServer:
     def __init__(self, hass, server_config, known_server_id=None, options=None):
         """Initialize a Plex server instance."""
         self.hass = hass
+        self._plex_account = None
         self._plex_server = None
         self._created_clients = set()
         self._known_clients = set()
@@ -85,6 +86,13 @@ class PlexServer:
         plexapi.myplex.BASE_HEADERS = plexapi.reset_base_headers()
         plexapi.server.BASE_HEADERS = plexapi.reset_base_headers()
 
+    @property
+    def account(self):
+        """Return a MyPlexAccount instance."""
+        if not self._plex_account:
+            self._plex_account = plexapi.myplex.MyPlexAccount(token=self._token)
+        return self._plex_account
+
     def connect(self):
         """Connect to a Plex server directly, obtaining direct URL if necessary."""
         config_entry_update_needed = False
diff --git a/homeassistant/components/plex/services.yaml b/homeassistant/components/plex/services.yaml
new file mode 100644
index 00000000000..0245edfb99e
--- /dev/null
+++ b/homeassistant/components/plex/services.yaml
@@ -0,0 +1,13 @@
+play_on_sonos:
+  description: Play music hosted on a Plex server on a linked Sonos speaker.
+  fields:
+    entity_id:
+      description: Entity ID of a media_player from the Sonos integration.
+      example: "media_player.sonos_living_room"
+    media_content_id:
+      description: The ID of the content to play. See https://www.home-assistant.io/integrations/plex/#music for details.
+      example: >-
+          '{ "library_name": "Music", "artist_name": "Stevie Wonder" }'
+    media_content_type:
+      description: The type of content to play. Must be "music".
+      example: "music"
diff --git a/homeassistant/components/sonos/__init__.py b/homeassistant/components/sonos/__init__.py
index c3a977e32e1..f19816e865d 100644
--- a/homeassistant/components/sonos/__init__.py
+++ b/homeassistant/components/sonos/__init__.py
@@ -4,9 +4,11 @@ import voluptuous as vol
 from homeassistant import config_entries
 from homeassistant.components.media_player import DOMAIN as MP_DOMAIN
 from homeassistant.const import CONF_HOSTS
+from homeassistant.exceptions import HomeAssistantError
 from homeassistant.helpers import config_validation as cv
+from homeassistant.loader import bind_hass
 
-from .const import DOMAIN
+from .const import DATA_SONOS, DOMAIN
 
 CONF_ADVERTISE_ADDR = "advertise_addr"
 CONF_INTERFACE_ADDR = "interface_addr"
@@ -53,3 +55,21 @@ async def async_setup_entry(hass, entry):
         hass.config_entries.async_forward_entry_setup(entry, MP_DOMAIN)
     )
     return True
+
+
+@bind_hass
+def get_coordinator_id(hass, entity_id):
+    """Obtain the unique_id of a device's coordinator.
+
+    This function is safe to run inside the event loop.
+    """
+    if DATA_SONOS not in hass.data:
+        raise HomeAssistantError("Sonos integration not set up")
+
+    device = next(
+        (x for x in hass.data[DATA_SONOS].entities if x.entity_id == entity_id), None
+    )
+
+    if device.is_coordinator:
+        return device.unique_id
+    return device.coordinator.unique_id
diff --git a/homeassistant/components/sonos/const.py b/homeassistant/components/sonos/const.py
index 5858f2bca9b..0d88249f740 100644
--- a/homeassistant/components/sonos/const.py
+++ b/homeassistant/components/sonos/const.py
@@ -1,3 +1,4 @@
 """Const for Sonos."""
 
 DOMAIN = "sonos"
+DATA_SONOS = "sonos_media_player"
diff --git a/homeassistant/components/sonos/media_player.py b/homeassistant/components/sonos/media_player.py
index b4a0fb7d208..15a168047e9 100644
--- a/homeassistant/components/sonos/media_player.py
+++ b/homeassistant/components/sonos/media_player.py
@@ -47,6 +47,7 @@ from . import (
     CONF_ADVERTISE_ADDR,
     CONF_HOSTS,
     CONF_INTERFACE_ADDR,
+    DATA_SONOS,
     DOMAIN as SONOS_DOMAIN,
 )
 
@@ -70,8 +71,6 @@ SUPPORT_SONOS = (
     | SUPPORT_CLEAR_PLAYLIST
 )
 
-DATA_SONOS = "sonos_media_player"
-
 SOURCE_LINEIN = "Line-in"
 SOURCE_TV = "TV"
 
diff --git a/tests/components/plex/mock_classes.py b/tests/components/plex/mock_classes.py
index 0c082474eb2..2d69801e797 100644
--- a/tests/components/plex/mock_classes.py
+++ b/tests/components/plex/mock_classes.py
@@ -69,6 +69,10 @@ class MockPlexAccount:
         """Mock the PlexAccount resources listing method."""
         return self._resources
 
+    def sonos_speaker_by_id(self, machine_identifier):
+        """Mock the PlexAccount Sonos lookup method."""
+        return MockPlexSonosClient(machine_identifier)
+
 
 class MockPlexSystemAccount:
     """Mock a PlexSystemAccount instance."""
@@ -351,3 +355,15 @@ class MockPlexMediaTrack(MockPlexMediaItem):
         """Initialize the object."""
         super().__init__(f"Track {index}", "track")
         self.index = index
+
+
+class MockPlexSonosClient:
+    """Mock a PlexSonosClient instance."""
+
+    def __init__(self, machine_identifier):
+        """Initialize the object."""
+        self.machineIdentifier = machine_identifier
+
+    def playMedia(self, item):
+        """Mock the playMedia method."""
+        pass
diff --git a/tests/components/plex/test_playback.py b/tests/components/plex/test_playback.py
new file mode 100644
index 00000000000..7a90d8dfad8
--- /dev/null
+++ b/tests/components/plex/test_playback.py
@@ -0,0 +1,127 @@
+"""Tests for Plex player playback methods/services."""
+from homeassistant.components.media_player.const import (
+    ATTR_MEDIA_CONTENT_ID,
+    ATTR_MEDIA_CONTENT_TYPE,
+    MEDIA_TYPE_MUSIC,
+)
+from homeassistant.components.plex.const import DOMAIN, SERVERS, SERVICE_PLAY_ON_SONOS
+from homeassistant.const import ATTR_ENTITY_ID
+from homeassistant.exceptions import HomeAssistantError
+
+from .const import DEFAULT_DATA, DEFAULT_OPTIONS
+from .mock_classes import MockPlexAccount, MockPlexServer
+
+from tests.async_mock import patch
+from tests.common import MockConfigEntry
+
+
+async def test_sonos_playback(hass):
+    """Test playing media on a Sonos speaker."""
+
+    entry = MockConfigEntry(
+        domain=DOMAIN,
+        data=DEFAULT_DATA,
+        options=DEFAULT_OPTIONS,
+        unique_id=DEFAULT_DATA["server_id"],
+    )
+
+    mock_plex_server = MockPlexServer(config_entry=entry)
+
+    with patch("plexapi.server.PlexServer", return_value=mock_plex_server), patch(
+        "homeassistant.components.plex.PlexWebsocket.listen"
+    ):
+        entry.add_to_hass(hass)
+        assert await hass.config_entries.async_setup(entry.entry_id)
+        await hass.async_block_till_done()
+
+    server_id = mock_plex_server.machineIdentifier
+    loaded_server = hass.data[DOMAIN][SERVERS][server_id]
+
+    with patch("plexapi.myplex.MyPlexAccount", return_value=MockPlexAccount()):
+        # Access and cache PlexAccount
+        assert loaded_server.account
+
+    # Test Sonos integration lookup failure
+    with patch.object(
+        hass.components.sonos, "get_coordinator_id", side_effect=HomeAssistantError
+    ):
+        assert await hass.services.async_call(
+            DOMAIN,
+            SERVICE_PLAY_ON_SONOS,
+            {
+                ATTR_ENTITY_ID: "media_player.sonos_kitchen",
+                ATTR_MEDIA_CONTENT_TYPE: MEDIA_TYPE_MUSIC,
+                ATTR_MEDIA_CONTENT_ID: '{"library_name": "Music", "artist_name": "Artist", "album_name": "Album"}',
+            },
+            True,
+        )
+
+    # Test success with dict
+    with patch.object(
+        hass.components.sonos,
+        "get_coordinator_id",
+        return_value="media_player.sonos_kitchen",
+    ), patch("plexapi.playqueue.PlayQueue.create"):
+        assert await hass.services.async_call(
+            DOMAIN,
+            SERVICE_PLAY_ON_SONOS,
+            {
+                ATTR_ENTITY_ID: "media_player.sonos_kitchen",
+                ATTR_MEDIA_CONTENT_TYPE: MEDIA_TYPE_MUSIC,
+                ATTR_MEDIA_CONTENT_ID: "2",
+            },
+            True,
+        )
+
+    # Test success with plex_key
+    with patch.object(
+        hass.components.sonos,
+        "get_coordinator_id",
+        return_value="media_player.sonos_kitchen",
+    ), patch("plexapi.playqueue.PlayQueue.create"):
+        assert await hass.services.async_call(
+            DOMAIN,
+            SERVICE_PLAY_ON_SONOS,
+            {
+                ATTR_ENTITY_ID: "media_player.sonos_kitchen",
+                ATTR_MEDIA_CONTENT_TYPE: MEDIA_TYPE_MUSIC,
+                ATTR_MEDIA_CONTENT_ID: '{"library_name": "Music", "artist_name": "Artist", "album_name": "Album"}',
+            },
+            True,
+        )
+
+    # Test invalid Plex server requested
+    with patch.object(
+        hass.components.sonos,
+        "get_coordinator_id",
+        return_value="media_player.sonos_kitchen",
+    ):
+        assert await hass.services.async_call(
+            DOMAIN,
+            SERVICE_PLAY_ON_SONOS,
+            {
+                ATTR_ENTITY_ID: "media_player.sonos_kitchen",
+                ATTR_MEDIA_CONTENT_TYPE: MEDIA_TYPE_MUSIC,
+                ATTR_MEDIA_CONTENT_ID: '{"plex_server": "unknown_plex_server", "library_name": "Music", "artist_name": "Artist", "album_name": "Album"}',
+            },
+            True,
+        )
+
+    # Test no speakers available
+    with patch.object(
+        loaded_server.account, "sonos_speaker_by_id", return_value=None
+    ), patch.object(
+        hass.components.sonos,
+        "get_coordinator_id",
+        return_value="media_player.sonos_kitchen",
+    ):
+        assert await hass.services.async_call(
+            DOMAIN,
+            SERVICE_PLAY_ON_SONOS,
+            {
+                ATTR_ENTITY_ID: "media_player.sonos_kitchen",
+                ATTR_MEDIA_CONTENT_TYPE: MEDIA_TYPE_MUSIC,
+                ATTR_MEDIA_CONTENT_ID: '{"library_name": "Music", "artist_name": "Artist", "album_name": "Album"}',
+            },
+            True,
+        )