diff --git a/resources/lang/en.json b/resources/lang/en.json
index 9ab07da4d..ba3290ba5 100644
--- a/resources/lang/en.json
+++ b/resources/lang/en.json
@@ -1639,6 +1639,7 @@
     "join_discord": "Join Our Discord Community!",
     "join_server": "Join Server",
     "keep": "Keep Playing",
+    "match_cancelled": "Match cancelled — not all players spawned",
     "nation_won": "Nation {nation} has won!",
     "new_lobby": "New Lobby",
     "other_team": "{team} team has won!",
diff --git a/src/client/hud/layers/WinModal.ts b/src/client/hud/layers/WinModal.ts
index 8e95c876e..2ac37325f 100644
--- a/src/client/hud/layers/WinModal.ts
+++ b/src/client/hud/layers/WinModal.ts
@@ -277,7 +277,14 @@ export class WinModal extends LitElement implements Controller {
     const winUpdates = updates !== null ? updates[GameUpdateType.Win] : [];
     winUpdates.forEach((wu) => {
       if (wu.winner === undefined) {
-        // ...
+        // Match cancelled (e.g. a ranked 2v2 that didn't fill or fully
+        // spawn): the game ends with no winner. Still vote the result to the
+        // server so the record is archived winnerless (never ranked).
+        this.eventBus.emit(new SendWinnerEvent(undefined, wu.allPlayersStats));
+        this._title = translateText("win_modal.match_cancelled");
+        this.isWin = false;
+        history.replaceState(null, "", `${window.location.pathname}?replay`);
+        this.show();
       } else if (wu.winner[0] === "team") {
         this.eventBus.emit(new SendWinnerEvent(wu.winner, wu.allPlayersStats));
         if (wu.winner[1] === this.game.myPlayer()?.team()) {
diff --git a/src/core/execution/WinCheckExecution.ts b/src/core/execution/WinCheckExecution.ts
index 8b8664353..b8d510183 100644
--- a/src/core/execution/WinCheckExecution.ts
+++ b/src/core/execution/WinCheckExecution.ts
@@ -19,6 +19,8 @@ export class WinCheckExecution implements Execution {
 
   private mg: Game | null = null;
 
+  private checkedRankedSpawns = false;
+
   // Hard time limit (in seconds) to force a winner before the server's
   // maxGameDuration hard kill. 170mins (10 mins before 3hrs)
   private static readonly HARD_TIME_LIMIT_SECONDS = 170 * 60;
@@ -35,6 +37,10 @@ export class WinCheckExecution implements Execution {
     }
     if (this.mg === null) throw new Error("Not initialized");
 
+    if (this.checkRanked2v2Cancelled()) {
+      return;
+    }
+
     if (this.mg.config().gameConfig().gameMode === GameMode.FFA) {
       this.checkWinnerFFA();
     } else {
@@ -42,6 +48,39 @@ export class WinCheckExecution implements Execution {
     }
   }
 
+  // A ranked 2v2 match is void unless all four matched players actually
+  // spawned — a player who never joined isn't in the game at all, and one who
+  // idled through the spawn phase never placed a spawn. Either way the match
+  // would be lopsided, so end it with no winner (the record is archived
+  // winnerless and never ranked). Runs once, on the first check after the
+  // spawn phase ends (this execution is inactive during the spawn phase).
+  private checkRanked2v2Cancelled(): boolean {
+    if (this.mg === null) throw new Error("Not initialized");
+    if (this.checkedRankedSpawns) {
+      return false;
+    }
+    this.checkedRankedSpawns = true;
+    const gameConfig = this.mg.config().gameConfig();
+    if (gameConfig.rankedType !== RankedType.TwoVTwo) {
+      return false;
+    }
+    // allPlayers: players() hides tile-less players, which is exactly what a
+    // never-spawned player is.
+    const spawned = this.mg
+      .allPlayers()
+      .filter((p) => p.type() === PlayerType.Human && p.hasSpawned()).length;
+    const expected = gameConfig.maxPlayers ?? 0;
+    if (spawned >= expected) {
+      return false;
+    }
+    console.log(
+      `ranked 2v2 cancelled: only ${spawned}/${expected} players spawned`,
+    );
+    this.mg.setWinner(null, this.mg.stats().stats());
+    this.active = false;
+    return true;
+  }
+
   checkWinnerFFA(): void {
     if (this.mg === null) throw new Error("Not initialized");
     const sorted = this.mg
diff --git a/src/core/game/Game.ts b/src/core/game/Game.ts
index 9fd7cc4ed..854c81d8a 100644
--- a/src/core/game/Game.ts
+++ b/src/core/game/Game.ts
@@ -762,7 +762,12 @@ export interface Game extends GameMap {
   drainPackedMotionPlans(): Uint32Array | null;
   drainPackedPlayerUpdates(): Float64Array | null;
   drainPackedAttackUpdates(): Float64Array | null;
-  setWinner(winner: Player | Team, allPlayersStats: AllPlayersStats): void;
+  // null ends the game with no winner (a cancelled match, e.g. a ranked game
+  // that didn't fill): the record is archived winnerless and never ranked.
+  setWinner(
+    winner: Player | Team | null,
+    allPlayersStats: AllPlayersStats,
+  ): void;
   getWinner(): Player | Team | null;
   config(): Config;
   isPaused(): boolean;
diff --git a/src/core/game/GameImpl.ts b/src/core/game/GameImpl.ts
index aae76222d..bfb93de78 100644
--- a/src/core/game/GameImpl.ts
+++ b/src/core/game/GameImpl.ts
@@ -890,7 +890,10 @@ export class GameImpl implements Game {
     });
   }
 
-  setWinner(winner: Player | Team, allPlayersStats: AllPlayersStats): void {
+  setWinner(
+    winner: Player | Team | null,
+    allPlayersStats: AllPlayersStats,
+  ): void {
     this._winner = winner;
     // OFM: snapshot final tiles for standings (bots skipped in recordFinalTiles).
     for (const player of this.players()) {
@@ -898,7 +901,7 @@ export class GameImpl implements Game {
     }
     this.addUpdate({
       type: GameUpdateType.Win,
-      winner: this.makeWinner(winner),
+      winner: winner === null ? undefined : this.makeWinner(winner),
       allPlayersStats,
     });
   }
diff --git a/src/server/GameServer.ts b/src/server/GameServer.ts
index dca022bde..7617402b2 100644
--- a/src/server/GameServer.ts
+++ b/src/server/GameServer.ts
@@ -1591,8 +1591,9 @@ export class GameServer {
     }
     client.reportedWinner = clientMsg.winner;
 
-    // Add client vote
-    const winnerKey = JSON.stringify(clientMsg.winner);
+    // Add client vote. A cancelled match ends with winner omitted;
+    // JSON.stringify(undefined) is not a string, so key those votes as "null".
+    const winnerKey = JSON.stringify(clientMsg.winner ?? null);
     const activeUniqueIPs = new Set(this.activeClients.map((c) => c.ip)).size;
     const votes = this.winnerVotes.add(winnerKey, clientMsg, client.ip);
 
diff --git a/tests/Ranked2v2Cancel.test.ts b/tests/Ranked2v2Cancel.test.ts
new file mode 100644
index 000000000..8920f636f
--- /dev/null
+++ b/tests/Ranked2v2Cancel.test.ts
@@ -0,0 +1,103 @@
+import { WinCheckExecution } from "../src/core/execution/WinCheckExecution";
+import {
+  Game,
+  GameMode,
+  PlayerInfo,
+  PlayerType,
+  RankedType,
+} from "../src/core/game/Game";
+import { GameUpdateType, WinUpdate } from "../src/core/game/GameUpdates";
+import { GameConfig } from "../src/core/Schemas";
+import { setup } from "./util/Setup";
+
+async function setupTeamGame(config: Partial<GameConfig>): Promise<Game> {
+  const players = [1, 2, 3, 4].map(
+    (n) =>
+      new PlayerInfo(`player${n}`, PlayerType.Human, `client${n}`, `p${n}_id`),
+  );
+  return setup(
+    "plains",
+    {
+      gameMode: GameMode.Team,
+      playerTeams: 2,
+      maxPlayers: 4,
+      ...config,
+    },
+    players,
+  );
+}
+
+function spawnPlayers(game: Game, count: number) {
+  for (let n = 1; n <= count; n++) {
+    const player = game.player(`p${n}_id`);
+    player.setSpawnTile(game.map().ref(n, n));
+  }
+}
+
+// The check fires on the first WinCheckExecution tick after the spawn phase
+// (ticks divisible by 10), so 11 ticks is always enough to reach it.
+function collectWinUpdates(game: Game): WinUpdate[] {
+  game.addExecution(new WinCheckExecution());
+  const wins: WinUpdate[] = [];
+  for (let i = 0; i < 11; i++) {
+    wins.push(...game.executeNextTick()[GameUpdateType.Win]);
+  }
+  return wins;
+}
+
+describe("Ranked 2v2 cancellation", () => {
+  it("ends the game with no winner when only 3 of 4 players spawned", async () => {
+    const game = await setupTeamGame({ rankedType: RankedType.TwoVTwo });
+    spawnPlayers(game, 3);
+
+    const wins = collectWinUpdates(game);
+
+    expect(wins).toHaveLength(1);
+    expect(wins[0].winner).toBeUndefined();
+    expect(game.getWinner()).toBeNull();
+  });
+
+  it("ends the game with no winner when a player never joined", async () => {
+    // Only 3 players are in the game at all (the 4th never connected, so it
+    // isn't in the start info), even though all present players spawned.
+    const players = [1, 2, 3].map(
+      (n) =>
+        new PlayerInfo(
+          `player${n}`,
+          PlayerType.Human,
+          `client${n}`,
+          `p${n}_id`,
+        ),
+    );
+    const game = await setup(
+      "plains",
+      {
+        gameMode: GameMode.Team,
+        playerTeams: 2,
+        maxPlayers: 4,
+        rankedType: RankedType.TwoVTwo,
+      },
+      players,
+    );
+    spawnPlayers(game, 3);
+
+    const wins = collectWinUpdates(game);
+
+    expect(wins).toHaveLength(1);
+    expect(wins[0].winner).toBeUndefined();
+  });
+
+  it("does not cancel when all 4 players spawned", async () => {
+    const game = await setupTeamGame({ rankedType: RankedType.TwoVTwo });
+    spawnPlayers(game, 4);
+
+    expect(collectWinUpdates(game)).toHaveLength(0);
+  });
+
+  it("does not cancel unranked team games that are short a player", async () => {
+    const game = await setupTeamGame({});
+    spawnPlayers(game, 3);
+
+    expect(collectWinUpdates(game)).toHaveLength(0);
+  });
+});