diff --git a/packages/@ember/string/index.ts b/packages/@ember/string/index.ts
index 7c9cb1df0a9..a242eb9c8d1 100644
--- a/packages/@ember/string/index.ts
+++ b/packages/@ember/string/index.ts
@@ -53,7 +53,7 @@ const UNDERSCORE_CACHE = new Cache<string, string>(1000, str =>
     .toLowerCase()
 );
 
-const STRING_CAPITALIZE_REGEXP = /(^|\/)([a-z\u00C0-\u024F])/g;
+const STRING_CAPITALIZE_REGEXP = /(^|(?<!\/)\/(?!\/))([a-z\u00C0-\u024F])/g;
 
 const CAPITALIZE_CACHE = new Cache<string, string>(1000, str =>
   str.replace(STRING_CAPITALIZE_REGEXP, (match /*, separator, chr */) => match.toUpperCase())
diff --git a/packages/@ember/string/tests/capitalize_test.js b/packages/@ember/string/tests/capitalize_test.js
index 3f5951802c5..1f9c6d2eba6 100644
--- a/packages/@ember/string/tests/capitalize_test.js
+++ b/packages/@ember/string/tests/capitalize_test.js
@@ -52,6 +52,12 @@ moduleFor(
         'Private-docs/Owner-invoice',
         'capitalize namespaced dasherized string'
       );
+      test(
+        assert,
+        'url is http://www.emberjs.com, not http:///www.emberjs.com',
+        'Url is http://www.emberjs.com, not http:///www.emberjs.com',
+        'does nothing with multiple slashes'
+      );
       test(assert, 'šabc', 'Šabc', 'capitalize string with accent character');
     }
   }