diff --git a/packages/react-native/src/private/webapis/dom/events/CustomEvent.js b/packages/react-native/src/private/webapis/dom/events/CustomEvent.js
index 25d046b2709..9e535563ced 100644
--- a/packages/react-native/src/private/webapis/dom/events/CustomEvent.js
+++ b/packages/react-native/src/private/webapis/dom/events/CustomEvent.js
@@ -19,10 +19,10 @@ import type {EventInit} from './Event';
 
 import Event from './Event';
 
-export type CustomEventInit = {
+export type CustomEventInit = $ReadOnly<{
   ...EventInit,
   detail?: mixed,
-};
+}>;
 
 export default class CustomEvent extends Event {
   _detail: mixed;
diff --git a/packages/react-native/src/private/webapis/dom/events/Event.js b/packages/react-native/src/private/webapis/dom/events/Event.js
index 10ccd67061e..79853f509f5 100644
--- a/packages/react-native/src/private/webapis/dom/events/Event.js
+++ b/packages/react-native/src/private/webapis/dom/events/Event.js
@@ -36,11 +36,11 @@ import {
   setStopPropagationFlag,
 } from './internals/EventInternals';
 
-export type EventInit = {
+export type EventInit = $ReadOnly<{
   bubbles?: boolean,
   cancelable?: boolean,
   composed?: boolean,
-};
+}>;
 
 export default class Event {
   static +NONE: 0;
diff --git a/packages/react-native/src/private/webapis/dom/events/EventTarget.js b/packages/react-native/src/private/webapis/dom/events/EventTarget.js
index 9697800ac35..5e70029d046 100644
--- a/packages/react-native/src/private/webapis/dom/events/EventTarget.js
+++ b/packages/react-native/src/private/webapis/dom/events/EventTarget.js
@@ -39,16 +39,16 @@ export type EventHandler = interface {
 };
 export type EventListener = EventCallback | EventHandler;
 
-export type EventListenerOptions = {
+export type EventListenerOptions = $ReadOnly<{
   capture?: boolean,
-};
+}>;
 
-export type AddEventListenerOptions = {
+export type AddEventListenerOptions = $ReadOnly<{
   ...EventListenerOptions,
   passive?: boolean,
   once?: boolean,
   signal?: AbortSignal,
-};
+}>;
 
 type EventListenerRegistration = {
   +callback: EventListener,