diff --git a/.changeset/fix-event-serial.md b/.changeset/fix-event-serial.md
new file mode 100644
index 000000000000..a3f94086b71a
--- /dev/null
+++ b/.changeset/fix-event-serial.md
@@ -0,0 +1,5 @@
+---
+"opencode": patch
+---
+
+Run EventV2 serial dispatch listeners sequentially instead of concurrently.
diff --git a/packages/core/src/event.ts b/packages/core/src/event.ts
index 35c14d23d92b..acdd595b11d2 100644
--- a/packages/core/src/event.ts
+++ b/packages/core/src/event.ts
@@ -683,10 +683,7 @@ export const layerWith = (options?: LayerOptions) =>
       ): Effect.Effect<ReadonlyArray<R>> =>
         Effect.suspend(() => {
           const event = placeholderEvent<D>(definition)
-          return Effect.forEach(listeners, (listener) => listener(event), {
-            concurrency: "unbounded",
-            discard: false,
-          })
+          return Effect.forEach(listeners, (listener) => listener(event))
         })
 
       const parallel = <D extends Definition, R>(
diff --git a/packages/core/test/event.test.ts b/packages/core/test/event.test.ts
index e4329a2dde98..4396a792e893 100644
--- a/packages/core/test/event.test.ts
+++ b/packages/core/test/event.test.ts
@@ -268,6 +268,57 @@ describe("EventV2", () => {
     }),
   )
 
+  it.effect("runs serial dispatch listeners one at a time", () =>
+    Effect.gen(function* () {
+      const events = yield* EventV2.Service
+      const firstStarted = yield* Deferred.make<void>()
+      const releaseFirst = yield* Deferred.make<void>()
+      const secondStarted = yield* Deferred.make<void>()
+      const dispatch = yield* events
+        .serial(Message, [
+          () =>
+            Deferred.succeed(firstStarted, undefined).pipe(
+              Effect.andThen(Deferred.await(releaseFirst)),
+              Effect.as("first"),
+            ),
+          () => Deferred.succeed(secondStarted, undefined).pipe(Effect.as("second")),
+        ])
+        .pipe(Effect.forkChild)
+
+      yield* Deferred.await(firstStarted)
+      yield* Effect.yieldNow
+      expect(yield* Deferred.isDone(secondStarted)).toBe(false)
+
+      yield* Deferred.succeed(releaseFirst, undefined)
+      expect(yield* Fiber.join(dispatch)).toEqual(["first", "second"])
+      expect(yield* Deferred.isDone(secondStarted)).toBe(true)
+    }),
+  )
+
+  it.effect("runs parallel dispatch listeners concurrently", () =>
+    Effect.gen(function* () {
+      const events = yield* EventV2.Service
+      const firstStarted = yield* Deferred.make<void>()
+      const releaseFirst = yield* Deferred.make<void>()
+      const secondStarted = yield* Deferred.make<void>()
+      const dispatch = yield* events
+        .parallel(Message, [
+          () =>
+            Deferred.succeed(firstStarted, undefined).pipe(
+              Effect.andThen(Deferred.await(releaseFirst)),
+              Effect.as("first"),
+            ),
+          () => Deferred.succeed(secondStarted, undefined).pipe(Effect.as("second")),
+        ])
+        .pipe(Effect.forkChild)
+
+      yield* Deferred.await(firstStarted)
+      yield* Deferred.await(secondStarted)
+      yield* Deferred.succeed(releaseFirst, undefined)
+      expect(yield* Fiber.join(dispatch)).toEqual(["first", "second"])
+    }),
+  )
+
   it.effect("isolates observer defects after durable events commit", () =>
     Effect.gen(function* () {
       const events = yield* EventV2.Service