diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9d5c51c220..5d7aec805c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,9 @@ released.
 
 ### Added
 
+- Added support for sending and receiving client themes.
+  ([#3209](https://github.com/Pycord-Development/pycord/pull/3209))
+
 ### Changed
 
 ### Fixed
diff --git a/discord/__init__.py b/discord/__init__.py
index 120069b750..76a80a18a7 100644
--- a/discord/__init__.py
+++ b/discord/__init__.py
@@ -68,6 +68,7 @@
 from .role import *
 from .scheduled_events import *
 from .shard import *
+from .shared_client_theme import *
 from .soundboard import *
 from .stage_instance import *
 from .sticker import *
diff --git a/discord/abc.py b/discord/abc.py
index 4b6ca924aa..5d13c6d4db 100644
--- a/discord/abc.py
+++ b/discord/abc.py
@@ -56,6 +56,7 @@
 from .permissions import PermissionOverwrite, Permissions
 from .role import Role
 from .scheduled_events import ScheduledEvent
+from .shared_client_theme import SharedClientThemeBaseType
 from .sticker import GuildSticker, StickerItem
 from .utils import warn_deprecated
 
@@ -89,6 +90,7 @@
     from .member import Member
     from .message import Message, MessageReference, PartialMessage
     from .poll import Poll
+    from .shared_client_theme import SharedClientTheme
     from .state import ConnectionState
     from .threads import Thread
     from .types.channel import Channel as ChannelPayload
@@ -1388,6 +1390,7 @@ async def send(
         suppress: bool = ...,
         suppress_embeds: bool = ...,
         silent: bool = ...,
+        shared_client_theme: SharedClientTheme = ...,
     ) -> Message: ...
 
     @overload
@@ -1410,6 +1413,7 @@ async def send(
         suppress: bool = ...,
         suppress_embeds: bool = ...,
         silent: bool = ...,
+        shared_client_theme: SharedClientTheme = ...,
     ) -> Message: ...
 
     @overload
@@ -1432,6 +1436,7 @@ async def send(
         suppress: bool = ...,
         suppress_embeds: bool = ...,
         silent: bool = ...,
+        shared_client_theme: SharedClientTheme = ...,
     ) -> Message: ...
 
     @overload
@@ -1454,6 +1459,7 @@ async def send(
         suppress: bool = ...,
         suppress_embeds: bool = ...,
         silent: bool = ...,
+        shared_client_theme: SharedClientTheme = ...,
     ) -> Message: ...
 
     async def send(
@@ -1477,6 +1483,7 @@ async def send(
         suppress=None,
         suppress_embeds=None,
         silent=None,
+        shared_client_theme=None,
     ):
         """|coro|
 
@@ -1568,6 +1575,10 @@ async def send(
             The poll to send.
 
             .. versionadded:: 2.6
+        shared_client_theme: :class:`SharedClientTheme`
+            The shared client theme to send.
+
+            .. versionadded:: 2.9
 
         Returns
         -------
@@ -1592,6 +1603,9 @@ async def send(
         state = self._state
         content = str(content) if content is not None else None
 
+        if shared_client_theme is not None:
+            shared_client_theme = shared_client_theme.to_dict()
+
         if embed is not None and embeds is not None:
             raise InvalidArgument(
                 "cannot pass both embed and embeds parameter to send()"
@@ -1706,6 +1720,7 @@ async def send(
                     components=components,
                     flags=flags.value,
                     poll=poll,
+                    shared_client_theme=shared_client_theme,
                 )
             finally:
                 for f in files:
@@ -1725,6 +1740,7 @@ async def send(
                 components=components,
                 flags=flags.value,
                 poll=poll,
+                shared_client_theme=shared_client_theme,
             )
 
         ret = state.create_message(channel=channel, data=data)
diff --git a/discord/enums.py b/discord/enums.py
index 802bb41535..4cc00da6e3 100644
--- a/discord/enums.py
+++ b/discord/enums.py
@@ -88,6 +88,7 @@
     "SelectDefaultValueType",
     "ApplicationEventWebhookStatus",
     "InviteTargetUsersJobStatusCode",
+    "SharedClientThemeBaseType",
 )
 
 
@@ -1212,6 +1213,14 @@ class InviteTargetUsersJobStatusCode(Enum):
     failed = 3
 
 
+class SharedClientThemeBaseType(Enum):
+    unset = 0
+    dark = 1
+    light = 2
+    darker = 3
+    midnight = 4
+
+
 T = TypeVar("T")
 
 
diff --git a/discord/http.py b/discord/http.py
index fc6ffb22c3..05aa10bf35 100644
--- a/discord/http.py
+++ b/discord/http.py
@@ -84,6 +84,7 @@
         poll,
         role,
         scheduled_events,
+        shared_client_theme,
         sticker,
         template,
         threads,
@@ -507,6 +508,7 @@ def send_message(
         components: list[components.Component] | None = None,
         flags: int | None = None,
         poll: poll.Poll | None = None,
+        shared_client_theme: shared_client_theme.SharedClientTheme | None = None,
     ) -> Response[message.Message]:
         r = Route("POST", "/channels/{channel_id}/messages", channel_id=channel_id)
         payload = {}
@@ -547,6 +549,9 @@ def send_message(
         if poll:
             payload["poll"] = poll
 
+        if shared_client_theme:
+            payload["shared_client_theme"] = shared_client_theme
+
         return self.request(r, json=payload)
 
     def send_typing(self, channel_id: Snowflake) -> Response[None]:
@@ -571,6 +576,7 @@ def send_multipart_helper(
         components: list[components.Component] | None = None,
         flags: int | None = None,
         poll: poll.Poll | None = None,
+        shared_client_theme: shared_client_theme.SharedClientTheme | None = None,
     ) -> Response[message.Message]:
         form = []
 
@@ -598,6 +604,9 @@ def send_multipart_helper(
         if poll:
             payload["poll"] = poll
 
+        if shared_client_theme:
+            payload["shared_client_theme"] = shared_client_theme
+
         attachments = []
         form.append({"name": "payload_json"})
         for index, file in enumerate(files):
@@ -641,6 +650,7 @@ def send_files(
         components: list[components.Component] | None = None,
         flags: int | None = None,
         poll: poll.Poll | None = None,
+        shared_client_theme: shared_client_theme.SharedClientTheme | None = None,
     ) -> Response[message.Message]:
         r = Route("POST", "/channels/{channel_id}/messages", channel_id=channel_id)
         return self.send_multipart_helper(
@@ -658,6 +668,7 @@ def send_files(
             components=components,
             flags=flags,
             poll=poll,
+            shared_client_theme=shared_client_theme,
         )
 
     def edit_multipart_helper(
diff --git a/discord/message.py b/discord/message.py
index 1781bf45f1..6986e98a88 100644
--- a/discord/message.py
+++ b/discord/message.py
@@ -58,6 +58,7 @@
 from .partial_emoji import PartialEmoji
 from .poll import Poll
 from .reaction import Reaction
+from .shared_client_theme import SharedClientTheme
 from .sticker import StickerItem
 from .threads import Thread
 from .utils import MISSING, escape_mentions, find, warn_deprecated
@@ -90,6 +91,7 @@
     from .types.message import MessageSnapshot as MessageSnapshotPayload
     from .types.message import Reaction as ReactionPayload
     from .types.poll import Poll as PollPayload
+    from .types.shared_client_theme import SharedClientTheme as SharedClientThemePayload
     from .types.snowflake import SnowflakeList
     from .types.threads import ThreadArchiveDuration
     from .types.user import User as UserPayload
@@ -1039,6 +1041,10 @@ class Message(Hashable):
         The poll associated with this message, if applicable.
 
         .. versionadded:: 2.6
+    shared_client_theme: Optional[:class:`SharedClientTheme`]
+        The shared client theme transmitted via this message, if applicable.
+
+        .. versionadded:: 2.9
     call: Optional[:class:`MessageCall`]
         The call information associated with this message, if applicable.
 
@@ -1087,6 +1093,7 @@ class Message(Hashable):
         "_poll",
         "call",
         "snapshots",
+        "shared_client_theme",
     )
 
     if TYPE_CHECKING:
@@ -1217,6 +1224,13 @@ def __init__(
         except KeyError:
             self.call = None
 
+        if shared_client_theme := data.get("shared_client_theme"):
+            self.shared_client_theme: SharedClientTheme | None = (
+                SharedClientTheme.from_dict(shared_client_theme)
+            )
+        else:
+            self.shared_client_theme = None
+
         for handler in ("author", "member", "mentions", "mention_roles"):
             try:
                 getattr(self, f"_handle_{handler}")(data[handler])
@@ -1328,6 +1342,9 @@ def _handle_poll(self, value: PollPayload) -> None:
         self._poll = Poll.from_dict(value, self)
         self._state.store_poll(self._poll, self.id)
 
+    def _handle_shared_client_theme(self, value: SharedClientThemePayload) -> None:
+        self.shared_client_theme = SharedClientTheme.from_dict(value)
+
     def _handle_author(self, author: UserPayload) -> None:
         self.author = self._state.store_user(author)
         if isinstance(self.guild, Guild):
diff --git a/discord/shared_client_theme.py b/discord/shared_client_theme.py
new file mode 100644
index 0000000000..63f4f90328
--- /dev/null
+++ b/discord/shared_client_theme.py
@@ -0,0 +1,131 @@
+"""
+The MIT License (MIT)
+
+Copyright (c) 2021-present Pycord Development
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+"""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+from typing import TYPE_CHECKING, Sequence
+
+from typing_extensions import Self
+
+from .colour import Colour
+from .enums import SharedClientThemeBaseType, try_enum
+from .utils import MISSING
+
+__all__ = ("SharedClientTheme",)
+
+
+if TYPE_CHECKING:
+    from .types.shared_client_theme import SharedClientTheme as SharedClientThemePayload
+
+
+@dataclass(init=False)
+class SharedClientTheme:
+    """Represents a shared client theme that can be sent in a message.
+
+    A shared client theme lets users transmit a customized Discord client
+    appearance (colors, gradient, and base mode) through a message.
+
+    .. versionadded:: 2.9
+
+    Attributes
+    ----------
+    colours: List[:class:`Colour`]
+        The colours of the theme. A maximum of 5 colours.
+    colors: List[:class:`Colour`]
+        Alias for :attr:`colours`.
+    gradient_angle: :class:`int`
+        The direction of the theme's colors, in degrees. Must be between ``0`` and ``360``.
+    base_mix: :class:`int`
+        The intensity of the theme's colors. Must be between ``0`` and ``100``.
+    base_theme: Optional[:class:`SharedClientThemeBaseType`]
+        The mode of the theme. Defaults to :attr:`SharedClientThemeBaseType.unset`,
+        which Discord treats as :attr:`SharedClientThemeBaseType.dark`.
+    """
+
+    gradient_angle: int = 0
+    base_mix: int = 0
+    colours: list[Colour]
+    base_theme: SharedClientThemeBaseType | None = SharedClientThemeBaseType.unset
+
+    def __init__(
+        self,
+        gradient_angle: int = 0,
+        base_mix: int = 0,
+        colors: Sequence[Colour] = MISSING,
+        colours: Sequence[Colour] = MISSING,
+        *,
+        base_theme: SharedClientThemeBaseType = SharedClientThemeBaseType.unset,
+    ) -> None:
+        colours = colours if colours is not MISSING else colors
+
+        if len(colours or []) > 5:
+            raise ValueError("colors or colours must contain at most 5 colours")
+        if colours is MISSING:
+            raise TypeError("colors or colours must be provided")
+
+        if not 0 <= gradient_angle <= 360:
+            raise ValueError("gradient_angle must be between 0 and 360")
+
+        if not 0 <= base_mix <= 100:
+            raise ValueError("base_mix must be between 0 and 100")
+
+        if base_theme is not None and not isinstance(
+            base_theme, SharedClientThemeBaseType
+        ):
+            raise TypeError("base_theme must be a SharedClientThemeBaseType or None")
+
+        self.gradient_angle = gradient_angle
+        self.base_mix = base_mix
+        self.colours = list(colours)
+        self.base_theme = base_theme
+
+    @property
+    def colors(self) -> list[Colour]:
+        return self.colours
+
+    def to_dict(self) -> SharedClientThemePayload:
+        payload: SharedClientThemePayload = {
+            "colors": [f"{c.value:0>6x}" for c in self.colours],
+            "gradient_angle": self.gradient_angle,
+            "base_mix": self.base_mix,
+        }
+        if self.base_theme is not None:
+            payload["base_theme"] = self.base_theme.value
+        return payload
+
+    @classmethod
+    def from_dict(cls, data: SharedClientThemePayload) -> Self:
+        base_theme_value = data.get("base_theme")
+        colours = [Colour(int(c, 16)) for c in data.get("colors", [])]
+        return cls(
+            colours=colours,
+            gradient_angle=data["gradient_angle"],
+            base_mix=data["base_mix"],
+            base_theme=(
+                try_enum(SharedClientThemeBaseType, base_theme_value)
+                if base_theme_value is not None
+                else None
+            ),
+        )
diff --git a/discord/types/message.py b/discord/types/message.py
index c6a48881c7..48f35e881a 100644
--- a/discord/types/message.py
+++ b/discord/types/message.py
@@ -33,6 +33,7 @@
 from .emoji import PartialEmoji
 from .member import Member, UserWithMember
 from .poll import Poll
+from .shared_client_theme import SharedClientTheme
 from .snowflake import Snowflake, SnowflakeList
 from .sticker import StickerItem
 from .threads import Thread
@@ -174,6 +175,7 @@ class Message(TypedDict):
     poll: Poll
     call: MessageCall
     message_snapshots: NotRequired[list[MessageSnapshot]]
+    shared_client_theme: NotRequired[SharedClientTheme]
 
 
 class MessagePin(TypedDict):
diff --git a/discord/types/shared_client_theme.py b/discord/types/shared_client_theme.py
new file mode 100644
index 0000000000..eebbcd0864
--- /dev/null
+++ b/discord/types/shared_client_theme.py
@@ -0,0 +1,36 @@
+"""
+The MIT License (MIT)
+
+Copyright (c) 2021-present Pycord Development
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the "Software"),
+to deal in the Software without restriction, including without limitation
+the rights to use, copy, modify, merge, publish, distribute, sublicense,
+and/or sell copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
+"""
+
+from typing import Literal, TypedDict
+
+from typing_extensions import NotRequired
+
+SharedClientThemeBaseType = Literal[0, 1, 2, 3, 4]
+
+
+class SharedClientTheme(TypedDict):
+    colors: list[str]
+    gradient_angle: int
+    base_mix: int
+    base_theme: NotRequired[SharedClientThemeBaseType]
diff --git a/docs/api/data_classes.rst b/docs/api/data_classes.rst
index a28cb2a726..7fbb16b0f1 100644
--- a/docs/api/data_classes.rst
+++ b/docs/api/data_classes.rst
@@ -89,6 +89,11 @@ Message
 .. autoclass:: File
     :members:
 
+.. attributetable:: SharedClientTheme
+
+.. autoclass:: SharedClientTheme
+    :members:
+
 Embed
 ~~~~~
 
diff --git a/docs/api/enums.rst b/docs/api/enums.rst
index efa16a4a5e..6a526594b2 100644
--- a/docs/api/enums.rst
+++ b/docs/api/enums.rst
@@ -2529,6 +2529,33 @@ of :class:`enum.Enum`.
         Represents the default layout.
 
 
+.. class:: SharedClientThemeBaseType
+
+    The base theme mode of a :class:`SharedClientTheme`.
+
+    .. versionadded:: 2.9
+
+    .. attribute:: unset
+
+        No explicit base theme. Treated as :attr:`dark` by Discord.
+
+    .. attribute:: dark
+
+        The dark base theme.
+
+    .. attribute:: light
+
+        The light base theme.
+
+    .. attribute:: darker
+
+        The darker base theme.
+
+    .. attribute:: midnight
+
+        The midnight base theme.
+
+
 .. class:: IntegrationType
 
     The integration type for an application.