diff --git a/browser-tests/cleanup.html b/browser-tests/cleanup.html
new file mode 100644
index 00000000..f6f2df63
--- /dev/null
+++ b/browser-tests/cleanup.html
@@ -0,0 +1,48 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <title>Cacophony native source cleanup</title>
+  </head>
+  <body>
+    <script type="module">
+      import { Cacophony } from "/src/cacophony.ts";
+
+      window.runCleanupCheck = async (scheduled) => {
+        if (typeof OfflineAudioContext === "undefined") return { supported: false };
+        const sampleRate = 48_000;
+        const length = 4_800;
+        const context = new OfflineAudioContext(2, length, sampleRate);
+        const cacophony = Cacophony.createOffline(
+          { context, length, numberOfChannels: 2, sampleRate },
+          undefined,
+          { autoUnlock: false, quiet: true },
+        );
+        let timer;
+        try {
+          const buffer = context.createBuffer(2, context.sampleRate * 6, context.sampleRate);
+          const sound = await cacophony.createSound(buffer, "buffer", "stereo");
+          const [voice] = sound.play({
+            at: context.currentTime + (scheduled ? 60 : 0),
+            loopCount: "infinite",
+          });
+          const source = voice.source;
+          const ended = new Promise((resolve) => source.addEventListener("ended", () => resolve(true), { once: true }));
+          // Exercise the client-facing Sound.cleanup cascade, keeping the asset alive.
+          sound.cleanup();
+          // Pull the silent source during offline rendering: WebKit does not process
+          // disconnected sources. Reconnecting must not revive a terminated voice.
+          source.connect(context.destination);
+          await context.startRendering();
+          const terminated = await Promise.race([
+            ended,
+            new Promise((resolve) => { timer = setTimeout(() => resolve(false), 3000); }),
+          ]);
+          return { supported: true, terminated, bufferPreserved: sound.buffer === buffer };
+        } finally {
+          clearTimeout(timer);
+        }
+      };
+    </script>
+  </body>
+</html>
diff --git a/browser-tests/cleanup.spec.ts b/browser-tests/cleanup.spec.ts
new file mode 100644
index 00000000..72ceb43a
--- /dev/null
+++ b/browser-tests/cleanup.spec.ts
@@ -0,0 +1,25 @@
+import { expect, test } from "@playwright/test";
+
+declare global {
+  interface Window {
+    runCleanupCheck(scheduled: boolean): Promise<{
+      supported: boolean;
+      terminated?: boolean;
+      bufferPreserved?: boolean;
+    }>;
+  }
+}
+
+for (const scheduled of [false, true]) {
+  test(`cleanup terminates a native ${scheduled ? "scheduled" : "immediate"} looping source`, async ({ page }) => {
+    await page.goto("/browser-tests/cleanup.html");
+    const result = await page.evaluate((scheduled) => window.runCleanupCheck(scheduled), scheduled);
+    test.skip(
+      !result.supported && process.platform === "win32",
+      "The Windows WebKit build does not expose OfflineAudioContext",
+    );
+    expect(result.supported).toBe(true);
+    expect(result.terminated).toBe(true);
+    expect(result.bufferPreserved).toBe(true);
+  });
+}
diff --git a/src/playback.test.ts b/src/playback.test.ts
index 222cd5c7..fff819dd 100644
--- a/src/playback.test.ts
+++ b/src/playback.test.ts
@@ -585,6 +585,68 @@ describe("Playback cloning for media-element-backed playback", () => {
 });
 
 describe("Playback cleanup functionality", () => {
+  it.each([0, 60])("terminates a looping source scheduled at %s before disconnecting", (at) => {
+    const buffer = new AudioBuffer({ length: 44100, sampleRate: 44100 });
+    const sound = new Sound("test-url", buffer, audioContextMock, audioContextMock.createGain());
+    const [voice] = sound.play({ at, loopCount: "infinite" });
+    const source = voice.source as AudioBufferSourceNode;
+    const order: string[] = [];
+    const stop = vi.spyOn(source, "stop").mockImplementation(() => {
+      expect(source.onended).toBeNull();
+      order.push("stop");
+    });
+    vi.spyOn(source, "disconnect").mockImplementation(() => {
+      order.push("disconnect");
+    });
+
+    voice.cleanup();
+    voice.cleanup();
+
+    expect(stop).toHaveBeenCalledTimes(1);
+    expect(order.slice(0, 2)).toEqual(["stop", "disconnect"]);
+    expect(() => voice.play()).toThrow("cleaned up");
+    sound.cleanup();
+  });
+
+  it.each([
+    "unplayed",
+    "paused",
+    "stopped",
+  ] as const)("cleans a %s voice without stopping its source again", (state) => {
+    const buffer = new AudioBuffer({ length: 44100, sampleRate: 44100 });
+    const sound = new Sound("test-url", buffer, audioContextMock, audioContextMock.createGain());
+    const [voice] = sound.preplay();
+    if (state !== "unplayed") {
+      voice.play();
+      if (state === "paused") voice.pause();
+      else voice.stop();
+    }
+    const stop = vi.spyOn(voice.source as AudioBufferSourceNode, "stop");
+
+    voice.cleanup();
+
+    expect(stop).not.toHaveBeenCalled();
+    expect(voice.source).toBeUndefined();
+    sound.cleanup();
+  });
+
+  it("preserves sibling voices and the Sound buffer for future playback", () => {
+    const buffer = new AudioBuffer({ length: 44100, sampleRate: 44100 });
+    const sound = new Sound("test-url", buffer, audioContextMock, audioContextMock.createGain());
+    const [first] = sound.play();
+    const [sibling] = sound.play();
+    const siblingStop = vi.spyOn(sibling.source as AudioBufferSourceNode, "stop");
+
+    first.cleanup();
+
+    expect(siblingStop).not.toHaveBeenCalled();
+    expect(sibling.isPlaying).toBe(true);
+    const [next] = sound.play();
+    expect((next.source as AudioBufferSourceNode).buffer).toBe(buffer);
+    expect(next.isPlaying).toBe(true);
+    sound.cleanup();
+  });
+
   let playback: Playback;
   let buffer: AudioBuffer;
   let source: AudioBufferSourceNode;
diff --git a/src/playback.ts b/src/playback.ts
index 13381055..1f83f963 100644
--- a/src/playback.ts
+++ b/src/playback.ts
@@ -569,6 +569,11 @@ export class Playback extends BasePlayback implements BaseSound {
       mediaElement.load();
     } else if ("onended" in this.source) {
       this.source.onended = null;
+      // Disconnecting alone leaves a started source running, including native loops.
+      // Scheduled starts also have playing state; unplayed/paused/stopped sources do not need stop().
+      if ("stop" in this.source && this._state === "playing") {
+        this.source.stop();
+      }
     }
     this._offset = 0;
     this._startTime = 0;