diff --git a/src/utils.ts b/src/utils.ts
index fdd160a7..b9039e40 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -42,7 +42,10 @@ export function joinURL (base: string, ...input: string[]): string {
   let url = base || ''
 
   for (const i of input) {
-    url = withTrailingSlash(url) + withoutLeadingSlash(i)
+    const part = withoutLeadingSlash(i)
+    if (part !== '/') {
+      url = withTrailingSlash(url) + part
+    }
   }
 
   return url
diff --git a/test/join.test.ts b/test/join.test.ts
index bb75b118..5fb9313d 100644
--- a/test/join.test.ts
+++ b/test/join.test.ts
@@ -7,6 +7,7 @@ describe('joinURL', () => {
     { input: ['/'], out: '/' },
     { input: ['/a'], out: '/a' },
     { input: ['a', 'b'], out: 'a/b' },
+    { input: ['/', '/b'], out: '/b' },
     { input: ['a', 'b/', 'c'], out: 'a/b/c' },
     { input: ['a', 'b/', '/c'], out: 'a/b/c' }
   ]