diff --git a/src/games/controllers/games.lobby.controller.ts b/src/games/controllers/games.lobby.controller.ts
index 3106c57..cd8bf9f 100644
--- a/src/games/controllers/games.lobby.controller.ts
+++ b/src/games/controllers/games.lobby.controller.ts
@@ -152,7 +152,7 @@ export class LobbyController {
         HttpStatus.FORBIDDEN,
       );
     }
-    this.lobbyService.start(game);
+    await this.lobbyService.start(game);
     return;
   }
 
@@ -178,6 +178,20 @@ export class LobbyController {
         HttpStatus.BAD_REQUEST,
       );
     }
-    return this.lobbyService.joinGame(game, session.user);
+    return await this.lobbyService.joinGame(game, session.user);
+  }
+
+  @Post(':id/leave')
+  @ApiOperation({ summary: "Leave a game that hasn't already started" })
+  @UseGuards(AuthGuard)
+  async leave(
+    @Param('id') id: string,
+    @Session() session: Record<string, any>,
+    @Param('id', GamePipe) game: Document<Game> & Game,
+  ) {
+    if (game.started) {
+      throw new HttpException('Game already started', HttpStatus.BAD_REQUEST);
+    }
+    return await this.lobbyService.leaveGame(game, session.user);
   }
 }
diff --git a/src/games/services/games.lobby.service.ts b/src/games/services/games.lobby.service.ts
index 4d3dc31..099bde0 100644
--- a/src/games/services/games.lobby.service.ts
+++ b/src/games/services/games.lobby.service.ts
@@ -6,6 +6,7 @@ import mongoose, { Document, Model } from 'mongoose';
 import {
   ReadContainerDto,
   ReadGameDto,
+  ReadPlayerDto,
   ReadTeamDto,
 } from '../dto/read-games.dto';
 import { User } from 'src/users/schemas/user.entity';
@@ -15,6 +16,7 @@ import { StartingDeckDto, UpdateGameDto } from '../dto/update-game.dto';
 import { EventEmitter2 } from '@nestjs/event-emitter';
 import { GameService } from './games.service';
 import { WithTransaction } from '../utils';
+import { platform } from 'os';
 
 @Injectable()
 export class LobbyService {
@@ -72,6 +74,46 @@ export class LobbyService {
     return 'true!';
   }
 
+  @WithTransaction
+  async leaveGame(
+    game: Document<Game> & Game,
+    user: User,
+    session?: mongoose.mongo.ClientSession,
+  ) {
+    const team = game.teams.find((t) =>
+      t.players.find((p) => p.user._id.equals(user._id)),
+    );
+    if (team == undefined) {
+      throw new HttpException('User not in game', HttpStatus.FORBIDDEN);
+    }
+    if (game.owner._id.equals(user._id)) {
+      throw new HttpException(
+        'You cannot leave a game you own',
+        HttpStatus.FORBIDDEN,
+      );
+    }
+    const index = team.players.findIndex((p) => p.user._id.equals(user._id));
+    const player = team.players[index];
+    team.players.splice(index, 1);
+    this.eventEmitter.emit('sse.lobby', {
+      type: 'leaveGame',
+      player: new ReadPlayerDto(player),
+      game: game._id.toHexString(),
+    });
+    this.eventEmitter.emit('sse.game.' + game._id.toHexString(), {
+      type: 'leaveGame',
+      player: new ReadPlayerDto(player),
+    });
+    if (team.players.length == 0) {
+      const teamIndex = game.teams.indexOf(team);
+      game.teams.splice(teamIndex, 1);
+    }
+
+    await game.save({ session });
+
+    return 'true!';
+  }
+
   async findAll(): Promise<ReadGameDto[]> {
     const games = await this.gameModel.find().exec();
     return await Promise.all(