diff --git a/packages/runtime-core/__tests__/componentSlots.spec.ts b/packages/runtime-core/__tests__/componentSlots.spec.ts
index f08f1910cd4..708fb20c423 100644
--- a/packages/runtime-core/__tests__/componentSlots.spec.ts
+++ b/packages/runtime-core/__tests__/componentSlots.spec.ts
@@ -134,9 +134,11 @@ describe('component: slots', () => {
     }
 
     const oldSlots = {
-      header: 'header'
+      header: 'header',
+      footer: undefined
     }
     const newSlots = {
+      header: undefined,
       footer: 'footer'
     }
 
diff --git a/packages/runtime-core/src/componentSlots.ts b/packages/runtime-core/src/componentSlots.ts
index afc5f03933b..980ee799186 100644
--- a/packages/runtime-core/src/componentSlots.ts
+++ b/packages/runtime-core/src/componentSlots.ts
@@ -234,7 +234,7 @@ export const updateSlots = (
   // delete stale slots
   if (needDeletionCheck) {
     for (const key in slots) {
-      if (!isInternalKey(key) && !(key in deletionComparisonTarget)) {
+      if (!isInternalKey(key) && deletionComparisonTarget[key] == null) {
         delete slots[key]
       }
     }