diff --git a/src/utils/__tests__/openapi.test.ts b/src/utils/__tests__/openapi.test.ts
index 92057583b1..244ab63c22 100644
--- a/src/utils/__tests__/openapi.test.ts
+++ b/src/utils/__tests__/openapi.test.ts
@@ -381,6 +381,14 @@ describe('Utils', () => {
         'objects (Pet) or numbers <int64>',
       );
     });
+
+    it('should not pluralize display types that are already pluralized', () => {
+      expect(pluralizeType('strings')).toEqual('strings');
+      expect(pluralizeType('objects (Pet)')).toEqual('objects (Pet)');
+      expect(pluralizeType('strings <email>')).toEqual('strings <email>');
+      expect(pluralizeType('objects or strings')).toEqual('objects or strings');
+      expect(pluralizeType('objects (Pet) or numbers <int64>')).toEqual('objects (Pet) or numbers <int64>');
+    });
   });
 
   describe('openapi serializeParameter', () => {
diff --git a/src/utils/openapi.ts b/src/utils/openapi.ts
index 7eefb30dfe..2836cfedc2 100644
--- a/src/utils/openapi.ts
+++ b/src/utils/openapi.ts
@@ -579,6 +579,6 @@ export function extractExtensions(obj: object, showExtensions: string[] | true):
 export function pluralizeType(displayType: string): string {
   return displayType
     .split(' or ')
-    .map(type => type.replace(/^(string|object|number|integer|array|boolean)( ?.*)/, '$1s$2'))
+    .map(type => type.replace(/^(string|object|number|integer|array|boolean)s?( ?.*)/, '$1s$2'))
     .join(' or ');
 }