diff --git a/packages/query-core/src/queryClient.ts b/packages/query-core/src/queryClient.ts
index 62aebf93a6..15df263919 100644
--- a/packages/query-core/src/queryClient.ts
+++ b/packages/query-core/src/queryClient.ts
@@ -62,6 +62,7 @@ export class QueryClient {
   private defaultOptions: DefaultOptions
   private queryDefaults: QueryDefaults[]
   private mutationDefaults: MutationDefaults[]
+  private mountCount: number
   private unsubscribeFocus?: () => void
   private unsubscribeOnline?: () => void
 
@@ -72,6 +73,7 @@ export class QueryClient {
     this.defaultOptions = config.defaultOptions || {}
     this.queryDefaults = []
     this.mutationDefaults = []
+    this.mountCount = 0
 
     if (process.env.NODE_ENV !== 'production' && config.logger) {
       this.logger.error(
@@ -81,6 +83,9 @@ export class QueryClient {
   }
 
   mount(): void {
+    this.mountCount++
+    if (this.mountCount !== 1) return
+
     this.unsubscribeFocus = focusManager.subscribe(() => {
       if (focusManager.isFocused()) {
         this.resumePausedMutations()
@@ -96,8 +101,14 @@ export class QueryClient {
   }
 
   unmount(): void {
+    this.mountCount--
+    if (this.mountCount !== 0) return
+
     this.unsubscribeFocus?.()
+    this.unsubscribeFocus = undefined
+
     this.unsubscribeOnline?.()
+    this.unsubscribeOnline = undefined
   }
 
   isFetching(filters?: QueryFilters): number
diff --git a/packages/query-core/src/tests/queryClient.test.tsx b/packages/query-core/src/tests/queryClient.test.tsx
index 8a91ef4632..a8b5533b09 100644
--- a/packages/query-core/src/tests/queryClient.test.tsx
+++ b/packages/query-core/src/tests/queryClient.test.tsx
@@ -23,6 +23,7 @@ describe('queryClient', () => {
 
   afterEach(() => {
     queryClient.clear()
+    queryClient.unmount()
   })
 
   describe('defaultOptions', () => {
@@ -1466,6 +1467,75 @@ describe('queryClient', () => {
       mutationCacheResumePausedMutationsSpy.mockRestore()
       onlineManager.setOnline(undefined)
     })
+
+    test('should notify queryCache and mutationCache after multiple mounts and single unmount', async () => {
+      const testClient = createQueryClient()
+      testClient.mount()
+      testClient.mount()
+      testClient.unmount()
+
+      const queryCacheOnFocusSpy = jest.spyOn(
+        testClient.getQueryCache(),
+        'onFocus',
+      )
+      const queryCacheOnOnlineSpy = jest.spyOn(
+        testClient.getQueryCache(),
+        'onOnline',
+      )
+      const mutationCacheResumePausedMutationsSpy = jest.spyOn(
+        testClient.getMutationCache(),
+        'resumePausedMutations',
+      )
+
+      onlineManager.setOnline(true)
+      expect(queryCacheOnOnlineSpy).toHaveBeenCalledTimes(1)
+      expect(mutationCacheResumePausedMutationsSpy).toHaveBeenCalledTimes(1)
+
+      focusManager.setFocused(true)
+      expect(queryCacheOnFocusSpy).toHaveBeenCalledTimes(1)
+      expect(mutationCacheResumePausedMutationsSpy).toHaveBeenCalledTimes(2)
+
+      queryCacheOnFocusSpy.mockRestore()
+      queryCacheOnOnlineSpy.mockRestore()
+      mutationCacheResumePausedMutationsSpy.mockRestore()
+      focusManager.setFocused(undefined)
+      onlineManager.setOnline(undefined)
+    })
+
+    test('should not notify queryCache and mutationCache after multiple mounts/unmounts', async () => {
+      const testClient = createQueryClient()
+      testClient.mount()
+      testClient.mount()
+      testClient.unmount()
+      testClient.unmount()
+
+      const queryCacheOnFocusSpy = jest.spyOn(
+        testClient.getQueryCache(),
+        'onFocus',
+      )
+      const queryCacheOnOnlineSpy = jest.spyOn(
+        testClient.getQueryCache(),
+        'onOnline',
+      )
+      const mutationCacheResumePausedMutationsSpy = jest.spyOn(
+        testClient.getMutationCache(),
+        'resumePausedMutations',
+      )
+
+      onlineManager.setOnline(true)
+      expect(queryCacheOnOnlineSpy).not.toHaveBeenCalled()
+      expect(mutationCacheResumePausedMutationsSpy).not.toHaveBeenCalled()
+
+      focusManager.setFocused(true)
+      expect(queryCacheOnFocusSpy).not.toHaveBeenCalled()
+      expect(mutationCacheResumePausedMutationsSpy).not.toHaveBeenCalled()
+
+      queryCacheOnFocusSpy.mockRestore()
+      queryCacheOnOnlineSpy.mockRestore()
+      mutationCacheResumePausedMutationsSpy.mockRestore()
+      focusManager.setFocused(undefined)
+      onlineManager.setOnline(undefined)
+    })
   })
 
   describe('setMutationDefaults', () => {