diff --git a/src/mpd_now_playable/cocoa/now_playing.py b/src/mpd_now_playable/cocoa/now_playing.py
index 15225de..13681d7 100644
--- a/src/mpd_now_playable/cocoa/now_playing.py
+++ b/src/mpd_now_playable/cocoa/now_playing.py
@@ -78,6 +78,12 @@ def playback_state_to_cocoa(state: PlaybackState) -> MPMusicPlaybackState:
 	return mapping[state]
 
 
+def join_plural_field(field: list[str]) -> str | None:
+	if field:
+		return ", ".join(field)
+	return None
+
+
 def song_to_media_item(song: Song) -> NSMutableDictionary:
 	nowplaying_info = nothing_to_media_item()
 	nowplaying_info[MPNowPlayingInfoPropertyMediaType] = MPNowPlayingInfoMediaTypeAudio
@@ -88,12 +94,12 @@ def song_to_media_item(song: Song) -> NSMutableDictionary:
 	nowplaying_info[MPMediaItemPropertyPersistentID] = song_to_persistent_id(song)
 
 	nowplaying_info[MPMediaItemPropertyTitle] = song.title
-	nowplaying_info[MPMediaItemPropertyArtist] = song.artist
-	nowplaying_info[MPMediaItemPropertyAlbumTitle] = song.album
+	nowplaying_info[MPMediaItemPropertyArtist] = join_plural_field(song.artist)
+	nowplaying_info[MPMediaItemPropertyAlbumTitle] = join_plural_field(song.album)
 	nowplaying_info[MPMediaItemPropertyAlbumTrackNumber] = song.track
 	nowplaying_info[MPMediaItemPropertyDiscNumber] = song.disc
-	nowplaying_info[MPMediaItemPropertyGenre] = song.genre
-	nowplaying_info[MPMediaItemPropertyComposer] = song.composer
+	nowplaying_info[MPMediaItemPropertyGenre] = join_plural_field(song.genre)
+	nowplaying_info[MPMediaItemPropertyComposer] = join_plural_field(song.composer)
 	nowplaying_info[MPMediaItemPropertyPlaybackDuration] = song.duration
 
 	# MPD can't play back music at different rates, so we just want to set it
diff --git a/src/mpd_now_playable/mpd/artwork_cache.py b/src/mpd_now_playable/mpd/artwork_cache.py
index 6ec5a9a..3d9ed1b 100644
--- a/src/mpd_now_playable/mpd/artwork_cache.py
+++ b/src/mpd_now_playable/mpd/artwork_cache.py
@@ -6,6 +6,7 @@ from yarl import URL
 
 from ..cache import Cache, make_cache
 from ..tools.asyncio import run_background_task
+from ..tools.types import un_maybe_plural
 from .types import CurrentSongResponse, MpdStateHandler
 
 CACHE_TTL = 60 * 60  # seconds = 1 hour
@@ -16,9 +17,11 @@ class ArtCacheEntry(TypedDict):
 
 
 def calc_album_key(song: CurrentSongResponse) -> str:
-	artist = song.get("albumartist", song.get("artist", "Unknown Artist"))
-	album = song.get("album", "Unknown Album")
-	return ":".join(t.replace(":", "-") for t in (artist, album))
+	artist = sorted(
+		un_maybe_plural(song.get("albumartist", song.get("artist", "Unknown Artist")))
+	)
+	album = sorted(un_maybe_plural(song.get("album", "Unknown Album")))
+	return ":".join(";".join(t).replace(":", "-") for t in (artist, album))
 
 
 def calc_track_key(song: CurrentSongResponse) -> str:
diff --git a/src/mpd_now_playable/mpd/listener.py b/src/mpd_now_playable/mpd/listener.py
index 1a8c107..62229b0 100644
--- a/src/mpd_now_playable/mpd/listener.py
+++ b/src/mpd_now_playable/mpd/listener.py
@@ -9,7 +9,7 @@ from yarl import URL
 from ..config.model import MpdConfig
 from ..player import Player
 from ..song import PlaybackState, Song, SongListener
-from ..tools.types import convert_if_exists
+from ..tools.types import convert_if_exists, un_maybe_plural
 from .artwork_cache import MpdArtworkCache
 from .types import CurrentSongResponse, StatusResponse
 
@@ -27,11 +27,11 @@ def mpd_current_to_song(
 			current.get("musicbrainz_releasetrackid"), UUID
 		),
 		title=current.get("title"),
-		artist=current.get("artist"),
-		album=current.get("album"),
-		album_artist=current.get("albumartist"),
-		composer=current.get("composer"),
-		genre=current.get("genre"),
+		artist=un_maybe_plural(current.get("artist")),
+		album=un_maybe_plural(current.get("album")),
+		album_artist=un_maybe_plural(current.get("albumartist")),
+		composer=un_maybe_plural(current.get("composer")),
+		genre=un_maybe_plural(current.get("genre")),
 		track=convert_if_exists(current.get("track"), int),
 		disc=convert_if_exists(current.get("disc"), int),
 		duration=float(status["duration"]),
diff --git a/src/mpd_now_playable/mpd/types.py b/src/mpd_now_playable/mpd/types.py
index a5aa8a3..8782ddc 100644
--- a/src/mpd_now_playable/mpd/types.py
+++ b/src/mpd_now_playable/mpd/types.py
@@ -1,5 +1,7 @@
 from typing import Literal, NotRequired, Protocol, TypedDict
 
+from ..tools.types import MaybePlural
+
 
 class MpdStateHandler(Protocol):
 	async def get_art(self, file: str) -> bytes | None: ...
@@ -47,19 +49,19 @@ class StatusResponse(TypedDict):
 # tagged, since then it can pass more information on to Now Playing, but it
 # should work fine with completely untagged music too.
 class CurrentSongTags(TypedDict, total=False):
-	artist: str
-	albumartist: str
-	artistsort: str
-	albumartistsort: str
+	artist: MaybePlural[str]
+	albumartist: MaybePlural[str]
+	artistsort: MaybePlural[str]
+	albumartistsort: MaybePlural[str]
 	title: str
-	album: str
+	album: MaybePlural[str]
 	track: str
 	date: str
 	originaldate: str
-	composer: str
+	composer: MaybePlural[str]
 	disc: str
 	label: str
-	genre: str
+	genre: MaybePlural[str]
 	musicbrainz_albumid: str
 	musicbrainz_albumartistid: str
 	musicbrainz_releasetrackid: str
diff --git a/src/mpd_now_playable/song.py b/src/mpd_now_playable/song.py
index cf72cfa..76f17a8 100644
--- a/src/mpd_now_playable/song.py
+++ b/src/mpd_now_playable/song.py
@@ -21,18 +21,17 @@ class Song:
 	musicbrainz_trackid: UUID | None
 	musicbrainz_releasetrackid: UUID | None
 	title: str | None
-	artist: str | None
-	composer: str | None
-	album: str | None
-	album_artist: str | None
+	artist: list[str]
+	composer: list[str]
+	album: list[str]
+	album_artist: list[str]
 	track: int | None
 	disc: int | None
-	genre: str | None
+	genre: list[str]
 	duration: float
 	elapsed: float
 	art: bytes | None = field(repr=lambda a: "<has art>" if a else "<no art>")
 
 
 class SongListener(Protocol):
-	def update(self, song: Song | None) -> None:
-		...
+	def update(self, song: Song | None) -> None: ...
diff --git a/src/mpd_now_playable/tools/types.py b/src/mpd_now_playable/tools/types.py
index 7ee4ffe..1d0f5cc 100644
--- a/src/mpd_now_playable/tools/types.py
+++ b/src/mpd_now_playable/tools/types.py
@@ -1,11 +1,51 @@
-from typing import Callable, TypeVar
+from collections.abc import Callable
+from typing import Any, TypeAlias, TypeVar
 
-__all__ = ("convert_if_exists",)
+__all__ = (
+	"AnyExceptList",
+	"MaybePlural",
+	"convert_if_exists",
+	"un_maybe_plural",
+)
 
-T = TypeVar("T")
+# Accept as many types as possible that are not lists. Yes, having to identify
+# them manually like this is kind of a pain! TypeScript can express this
+# restriction using a conditional type, and with another conditional type it
+# can correctly type a version of un_maybe_plural that *does* accept lists, but
+# Python's type system isn't quite that bonkers powerful. Yet?
+AnyExceptList = (
+	int
+	| float
+	| complex
+	| bool
+	| str
+	| bytes
+	| set[Any]
+	| dict[Any, Any]
+	| tuple[Any, ...]
+	| Callable[[Any], Any]
+	| type
+)
 
 
-def convert_if_exists(value: str | None, converter: Callable[[str], T]) -> T | None:
+U = TypeVar("U")
+
+
+def convert_if_exists(value: str | None, converter: Callable[[str], U]) -> U | None:
 	if value is None:
 		return None
 	return converter(value)
+
+
+T = TypeVar("T", bound=AnyExceptList)
+MaybePlural: TypeAlias = list[T] | T
+
+
+def un_maybe_plural(value: MaybePlural[T] | None) -> list[T]:
+	match value:
+		case None:
+			return []
+		case list(values):
+			return values[:]
+		case item:
+			return [item]