diff --git a/packages/docusaurus/src/client/exports/__tests__/useBaseUrl.test.tsx b/packages/docusaurus/src/client/exports/__tests__/useBaseUrl.test.tsx
index 4cca965759..5478f7c358 100644
--- a/packages/docusaurus/src/client/exports/__tests__/useBaseUrl.test.tsx
+++ b/packages/docusaurus/src/client/exports/__tests__/useBaseUrl.test.tsx
@@ -77,6 +77,7 @@ describe('useBaseUrl', () => {
     expect(mockUseBaseUrl('/hello/foo', {absolute: true})).toBe(
       'https://docusaurus.io/docusaurus/hello/foo',
     );
+    expect(mockUseBaseUrl('/docusaurus')).toBe('/docusaurus/');
     expect(mockUseBaseUrl('/docusaurus/')).toBe('/docusaurus/');
     expect(mockUseBaseUrl('/docusaurus/hello')).toBe('/docusaurus/hello');
     expect(mockUseBaseUrl('#hello')).toBe('#hello');
@@ -143,6 +144,7 @@ describe('useBaseUrlUtils().withBaseUrl()', () => {
     expect(withBaseUrl('/hello/foo', {absolute: true})).toBe(
       'https://docusaurus.io/docusaurus/hello/foo',
     );
+    expect(withBaseUrl('/docusaurus')).toBe('/docusaurus/');
     expect(withBaseUrl('/docusaurus/')).toBe('/docusaurus/');
     expect(withBaseUrl('/docusaurus/hello')).toBe('/docusaurus/hello');
     expect(withBaseUrl('#hello')).toBe('#hello');
diff --git a/packages/docusaurus/src/client/exports/useBaseUrl.ts b/packages/docusaurus/src/client/exports/useBaseUrl.ts
index a709e29380..5ae4640a15 100644
--- a/packages/docusaurus/src/client/exports/useBaseUrl.ts
+++ b/packages/docusaurus/src/client/exports/useBaseUrl.ts
@@ -33,6 +33,12 @@ function addBaseUrl(
     return baseUrl + url.replace(/^\//, '');
   }
 
+  // /baseUrl -> /baseUrl/
+  // https://github.com/facebook/docusaurus/issues/6315
+  if (url === baseUrl.replace(/\/$/, '')) {
+    return baseUrl;
+  }
+
   // We should avoid adding the baseurl twice if it's already there
   const shouldAddBaseUrl = !url.startsWith(baseUrl);