diff --git a/packages/toolkit/src/query/tests/errorHandling.test.tsx b/packages/toolkit/src/query/tests/errorHandling.test.tsx
index c19b507ed6..a7cc2248fc 100644
--- a/packages/toolkit/src/query/tests/errorHandling.test.tsx
+++ b/packages/toolkit/src/query/tests/errorHandling.test.tsx
@@ -459,10 +459,10 @@ describe('error handling in a component', () => {
     baseQuery: fetchBaseQuery({ baseUrl: 'https://example.com' }),
     endpoints: (build) => ({
       update: build.mutation<typeof mockSuccessResponse, any>({
-        query: () => ({ url: 'success' }),
+        query: () => ({ url: '/success' }),
       }),
       failedUpdate: build.mutation<typeof mockSuccessResponse, any>({
-        query: () => ({ url: 'error' }),
+        query: () => ({ url: '/error' }),
       }),
     }),
   })
diff --git a/packages/toolkit/src/query/tests/queryFn.test.tsx b/packages/toolkit/src/query/tests/queryFn.test.tsx
index a285cd6d8a..58de9299e6 100644
--- a/packages/toolkit/src/query/tests/queryFn.test.tsx
+++ b/packages/toolkit/src/query/tests/queryFn.test.tsx
@@ -319,7 +319,7 @@ describe('usage scenario tests', () => {
             throw randomResult.error
           }
           const post = randomResult.data as Post
-          const result = await fetchWithBQ(`/post/${post.id}`)
+          const result = await fetchWithBQ(`post/${post.id}`)
           return result.data
             ? { data: result.data as Post }
             : { error: result.error as FetchBaseQueryError }
diff --git a/packages/toolkit/src/query/tests/utils.test.ts b/packages/toolkit/src/query/tests/utils.test.ts
index 4b111b2a00..6629a170a1 100644
--- a/packages/toolkit/src/query/tests/utils.test.ts
+++ b/packages/toolkit/src/query/tests/utils.test.ts
@@ -75,20 +75,17 @@ describe('isDocumentVisible', () => {
 
 describe('joinUrls', () => {
   test('correctly joins variations of relative urls', () => {
-    expect(joinUrls('/api/', '/banana')).toBe('/api/banana')
     expect(joinUrls('/api/', 'banana')).toBe('/api/banana')
 
-    expect(joinUrls('/api', 'banana')).toBe('/api/banana')
     expect(joinUrls('/api', '/banana/')).toBe('/api/banana/')
 
     expect(joinUrls('', '/banana')).toBe('/banana')
     expect(joinUrls('', 'banana')).toBe('banana')
+
+    expect(joinUrls('/api', '?foo=bar')).toBe('/api?foo=bar')
   })
 
   test('correctly joins variations of absolute urls', () => {
-    expect(joinUrls('https://example.com/api', 'banana')).toBe(
-      'https://example.com/api/banana'
-    )
     expect(joinUrls('https://example.com/api', '/banana')).toBe(
       'https://example.com/api/banana'
     )
@@ -96,8 +93,13 @@ describe('joinUrls', () => {
     expect(joinUrls('https://example.com/api/', 'banana')).toBe(
       'https://example.com/api/banana'
     )
-    expect(joinUrls('https://example.com/api/', '/banana/')).toBe(
-      'https://example.com/api/banana/'
+
+    expect(joinUrls('https://example.com/api/', '?foo=bar')).toBe(
+      'https://example.com/api/?foo=bar'
+    )
+
+    expect(joinUrls('https://example.com/api', '?foo=bar')).toBe(
+      'https://example.com/api?foo=bar'
     )
   })
 })
diff --git a/packages/toolkit/src/query/utils/joinUrls.ts b/packages/toolkit/src/query/utils/joinUrls.ts
index f675338611..e68cd32a7c 100644
--- a/packages/toolkit/src/query/utils/joinUrls.ts
+++ b/packages/toolkit/src/query/utils/joinUrls.ts
@@ -1,12 +1,6 @@
 import { isAbsoluteUrl } from './isAbsoluteUrl'
 
-const withoutTrailingSlash = (url: string) => url.replace(/\/$/, '')
-const withoutLeadingSlash = (url: string) => url.replace(/^\//, '')
-
-export function joinUrls(
-  base: string | undefined,
-  url: string | undefined
-): string {
+export function joinUrls(base?: string, url?: string): string {
   if (!base) {
     return url!
   }
@@ -18,8 +12,5 @@ export function joinUrls(
     return url
   }
 
-  base = withoutTrailingSlash(base)
-  url = withoutLeadingSlash(url)
-
-  return `${base}/${url}`
+  return `${base}${url}`;
 }