diff --git a/packages/runtime-core/__tests__/componentEmits.spec.ts b/packages/runtime-core/__tests__/componentEmits.spec.ts
index 86307275bf8..654ba17c4b0 100644
--- a/packages/runtime-core/__tests__/componentEmits.spec.ts
+++ b/packages/runtime-core/__tests__/componentEmits.spec.ts
@@ -415,6 +415,7 @@ describe('component: emit', () => {
       'test-event': null,
       fooBar: null,
       FooBaz: null,
+      once: null,
     }
     expect(isEmitListener(options, 'onClick')).toBe(true)
     expect(isEmitListener(options, 'onclick')).toBe(false)
@@ -428,6 +429,9 @@ describe('component: emit', () => {
     expect(isEmitListener(options, 'onFooBar')).toBe(true)
     // PascalCase option
     expect(isEmitListener(options, 'onFooBaz')).toBe(true)
+    // #8342
+    expect(isEmitListener(options, 'onOnceOnce')).toBe(true)
+    expect(isEmitListener(options, 'onOnce')).toBe(true)
   })
 
   test('does not emit after unmount', async () => {
diff --git a/packages/runtime-core/src/componentEmits.ts b/packages/runtime-core/src/componentEmits.ts
index 3c0a111aa3e..c8ef5c0883a 100644
--- a/packages/runtime-core/src/componentEmits.ts
+++ b/packages/runtime-core/src/componentEmits.ts
@@ -269,8 +269,11 @@ export function isEmitListener(
   if (__COMPAT__ && key.startsWith(compatModelEventPrefix)) {
     return true
   }
-
-  key = key.slice(2).replace(/Once$/, '')
+  key = key.slice(2)
+  // #8342
+  // e.g. emits: { once: null } -> onOnce、ononce
+  // Does not require regular expression processing
+  key = key.toLowerCase() === 'once' ? key : key.replace(/Once$/, '')
   return (
     hasOwn(options, key[0].toLowerCase() + key.slice(1)) ||
     hasOwn(options, hyphenate(key)) ||