diff --git a/lib/matrix_server/room_server.ex b/lib/matrix_server/room_server.ex
index 6693d85..c68fef7 100644
--- a/lib/matrix_server/room_server.ex
+++ b/lib/matrix_server/room_server.ex
@@ -15,7 +15,7 @@ defmodule MatrixServer.RoomServer do
 
   alias MatrixServer.{Repo, Room, Event, StateResolution, Account, JoinedRoom}
   alias MatrixServer.StateResolution.Authorization
-  alias MatrixServerWeb.Client.Request.{CreateRoom, Kick}
+  alias MatrixServerWeb.Client.Request.{CreateRoom, Kick, Ban}
 
   @registry MatrixServer.RoomServer.Registry
   @supervisor MatrixServer.RoomServer.Supervisor
@@ -130,6 +130,22 @@ defmodule MatrixServer.RoomServer do
     GenServer.call(pid, {:kick, account, request})
   end
 
+  @doc """
+  Ban a user from this room.
+  """
+  @spec ban(pid(), Account.t(), Ban.t()) :: :ok | {:error, atom()}
+  def ban(pid, account, request) do
+    GenServer.call(pid, {:ban, account, request})
+  end
+
+  @doc """
+  Unban a user from this room.
+  """
+  @spec unban(pid(), Account.t(), String.t()) :: :ok | {:error, atom()}
+  def unban(pid, account, user_id) do
+    GenServer.call(pid, {:unban, account, user_id})
+  end
+
   ### Implementation
 
   @impl true
@@ -268,7 +284,29 @@ defmodule MatrixServer.RoomServer do
     end
   end
 
-  @spec insert_single_event(Room.t(), t(), Event.t()) :: {:ok, t(), Room.t()} | {:error, atom()}
+  def handle_call(
+        {:ban, account, %Kick{user_id: user_id, reason: reason}},
+        _from,
+        %{room: room, state_set: state_set} = state
+      ) do
+    ban_event = Event.ban(room, account, user_id, reason)
+
+    case insert_single_event(room, state_set, ban_event) do
+      {:ok, {state_set, room}} -> {:reply, :ok, %{state | state_set: state_set, room: room}}
+      {:error, reason} -> {:reply, {:error, reason}, state}
+    end
+  end
+
+  def handle_call({:unban, account, user_id},_from,%{room: room, state_set: state_set} = state) do
+    unban_event = Event.unban(room, account, user_id)
+
+    case insert_single_event(room, state_set, unban_event) do
+      {:ok, {state_set, room}} -> {:reply, :ok, %{state | state_set: state_set, room: room}}
+      {:error, reason} -> {:reply, {:error, reason}, state}
+    end
+  end
+
+  @spec insert_single_event(Room.t(), t(), Event.t()) :: {:ok, {t(), Room.t()}} | {:error, atom()}
   defp insert_single_event(room, state_set, event) do
     Repo.transaction(fn ->
       case finalize_and_insert_event(event, state_set, room) do
diff --git a/lib/matrix_server/schema/event.ex b/lib/matrix_server/schema/event.ex
index eec5e6c..3da76eb 100644
--- a/lib/matrix_server/schema/event.ex
+++ b/lib/matrix_server/schema/event.ex
@@ -226,6 +226,31 @@ defmodule MatrixServer.Event do
     }
   end
 
+  @spec ban(Room.t(), Account.t(), String.t(), String.t() | nil) :: t()
+  def ban(room, sender, user_id, reason \\ nil) do
+    content = %{"membership" => "ban"}
+    content = if reason, do: Map.put(content, "reason", reason), else: content
+
+    %Event{
+      new(room, sender)
+      | type: "m.room.member",
+        state_key: user_id,
+        content: content
+    }
+  end
+
+  @spec unban(Room.t(), Account.t(), String.t()) :: t()
+  def unban(room, sender, user_id) do
+    %Event{
+      new(room, sender)
+      | type: "m.room.member",
+        state_key: user_id,
+        content: %{
+          "membership" => "leave"
+        }
+    }
+  end
+
   @spec is_control_event(t()) :: boolean()
   def is_control_event(%Event{type: "m.room.power_levels", state_key: ""}), do: true
   def is_control_event(%Event{type: "m.room.join_rules", state_key: ""}), do: true
diff --git a/lib/matrix_server_web/client/controllers/room_controller.ex b/lib/matrix_server_web/client/controllers/room_controller.ex
index 8b0ea8d..4b68336 100644
--- a/lib/matrix_server_web/client/controllers/room_controller.ex
+++ b/lib/matrix_server_web/client/controllers/room_controller.ex
@@ -6,7 +6,7 @@ defmodule MatrixServerWeb.Client.RoomController do
 
   alias MatrixServer.{Repo, Room, RoomServer}
   alias MatrixServer.Types.UserId
-  alias MatrixServerWeb.Client.Request.{CreateRoom, Kick}
+  alias MatrixServerWeb.Client.Request.{CreateRoom, Kick, Ban}
   alias Ecto.Changeset
   alias Plug.Conn
 
@@ -156,4 +156,55 @@ defmodule MatrixServerWeb.Client.RoomController do
       {:error, :not_found} -> put_error(conn, :not_found, "Room not found.")
     end
   end
+
+  @doc """
+  Ban a user in the room.
+
+  Action for POST /_matrix/client/r0/rooms/{roomId}/ban.
+  """
+  def ban(%Conn{assigns: %{account: account}} = conn, %{"room_id" => room_id} = params) do
+    with {:ok, request} <- Ban.parse(params),
+         {:ok, pid} <- RoomServer.get_room_server(room_id) do
+      case RoomServer.ban(pid, account, request) do
+        :ok ->
+          conn
+          |> send_resp(200, [])
+          |> halt()
+
+        {:error, _} ->
+          put_error(conn, :unknown)
+      end
+    else
+      {:error, %Ecto.Changeset{}} -> put_error(conn, :bad_json)
+      {:error, :not_found} -> put_error(conn, :not_found, "Room not found.")
+    end
+  end
+
+  @doc """
+  Unban a user from the room.
+
+  Action for POST /_matrix/client/r0/rooms/{roomId}/unban.
+  """
+  def unban(%Conn{assigns: %{account: account}} = conn, %{
+        "room_id" => room_id,
+        "user_id" => user_id
+      }) do
+    case RoomServer.get_room_server(room_id) do
+      {:ok, pid} ->
+        case RoomServer.unban(pid, account, user_id) do
+          :ok ->
+            conn
+            |> send_resp(200, [])
+            |> halt()
+
+          {:error, _} ->
+            put_error(conn, :unknown)
+        end
+
+      {:error, :not_found} ->
+        put_error(conn, :not_found, "The given room was not found.")
+    end
+  end
+
+  def unban(conn, _), do: put_error(conn, :missing_param)
 end
diff --git a/lib/matrix_server_web/client/request/ban.ex b/lib/matrix_server_web/client/request/ban.ex
new file mode 100644
index 0000000..8906ae6
--- /dev/null
+++ b/lib/matrix_server_web/client/request/ban.ex
@@ -0,0 +1,20 @@
+defmodule MatrixServerWeb.Client.Request.Ban do
+  use MatrixServerWeb.Request
+
+  @type t :: %__MODULE__{
+          user_id: String.t(),
+          reason: String.t() | nil
+        }
+
+  @primary_key false
+  embedded_schema do
+    field :user_id, :string
+    field :reason, :string
+  end
+
+  def changeset(data, params) do
+    data
+    |> cast(params, [:user_id, :reason])
+    |> validate_required([:user_id])
+  end
+end
diff --git a/lib/matrix_server_web/router.ex b/lib/matrix_server_web/router.ex
index 10a10e1..b7004fa 100644
--- a/lib/matrix_server_web/router.ex
+++ b/lib/matrix_server_web/router.ex
@@ -62,6 +62,8 @@ defmodule MatrixServerWeb.Router do
         post "/join", RoomController, :join
         post "/leave", RoomController, :leave
         post "/kick", RoomController, :kick
+        post "/ban", RoomController, :ban
+        post "/unban", RoomController, :unban
       end
     end
   end