diff --git a/packages/reactivity/src/effectScope.ts b/packages/reactivity/src/effectScope.ts
index 898a7cb0272..f7a2dc6f279 100644
--- a/packages/reactivity/src/effectScope.ts
+++ b/packages/reactivity/src/effectScope.ts
@@ -116,8 +116,12 @@ export class EffectScope {
   stop(fromParent?: boolean): void {
     if (this._active) {
       let i, l
-      for (i = 0, l = this.effects.length; i < l; i++) {
-        this.effects[i].stop()
+      // #5783
+      // effects will be changed when a watch stopped.
+      // so we need to copy it for iteration.
+      const effectsToStop = this.effects.slice()
+      for (i = 0, l = effectsToStop.length; i < l; i++) {
+        effectsToStop[i].stop()
       }
       for (i = 0, l = this.cleanups.length; i < l; i++) {
         this.cleanups[i]()
diff --git a/packages/runtime-core/__tests__/apiWatch.spec.ts b/packages/runtime-core/__tests__/apiWatch.spec.ts
index 85afec24ceb..40cb7d1ad59 100644
--- a/packages/runtime-core/__tests__/apiWatch.spec.ts
+++ b/packages/runtime-core/__tests__/apiWatch.spec.ts
@@ -1378,6 +1378,43 @@ describe('api: watch', () => {
     expect(spy).toHaveBeenCalledTimes(2)
   })
 
+  test('removing a watcher while stopping its effectScope', async () => {
+    const count = ref(0)
+    const scope = effectScope()
+    let watcherCalls = 0
+    let cleanupCalls = 0
+
+    scope.run(() => {
+      const stop1 = watch(count, () => {
+        watcherCalls++
+      })
+      watch(count, (val, old, onCleanup) => {
+        watcherCalls++
+        onCleanup(() => {
+          cleanupCalls++
+          stop1()
+        })
+      })
+      watch(count, () => {
+        watcherCalls++
+      })
+    })
+
+    expect(watcherCalls).toBe(0)
+    expect(cleanupCalls).toBe(0)
+
+    count.value++
+    await nextTick()
+    expect(watcherCalls).toBe(3)
+    expect(cleanupCalls).toBe(0)
+
+    scope.stop()
+    count.value++
+    await nextTick()
+    expect(watcherCalls).toBe(3)
+    expect(cleanupCalls).toBe(1)
+  })
+
   it('watching sources: ref<any[]>', async () => {
     const foo = ref([1])
     const spy = vi.fn()