diff --git a/src/types.ts b/src/types.ts
index 1455445..cf87e41 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -223,7 +223,14 @@ export type SourceLanguageCode = CommonLanguageCode | 'en' | 'pt';
  * Note: although the language code type definitions are case-sensitive, this package and the DeepL
  * API accept case-insensitive language codes.
  */
-export type TargetLanguageCode = CommonLanguageCode | 'en-GB' | 'en-US' | 'pt-BR' | 'pt-PT';
+export type TargetLanguageCode =
+    | CommonLanguageCode
+    | 'en-GB'
+    | 'en-US'
+    | 'pt-BR'
+    | 'pt-PT'
+    | 'zh-HANS'
+    | 'zh-HANT';
 
 /**
  * All language codes, including source-only and target-only language codes.
diff --git a/src/utils.ts b/src/utils.ts
index b988450..8e02009 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -167,6 +167,10 @@ export function buildURLSearchParams(
         throw new DeepLError(
             "targetLang='pt' is deprecated, please use 'pt-PT' or 'pt-BR' instead.",
         );
+    } else if (targetLang === 'zh') {
+        throw new DeepLError(
+            "targetLang='zh' is deprecated, please use 'zh-HANS' or 'zh-HANT' instead.",
+        );
     }
 
     const searchParams = new URLSearchParams({
diff --git a/tests/core.ts b/tests/core.ts
index d7583e8..5ab5ec2 100644
--- a/tests/core.ts
+++ b/tests/core.ts
@@ -45,6 +45,8 @@ const internalExampleText: Record<string, string> = {
     tr: 'proton ışını',
     uk: 'протонний пучок',
     zh: '质子束',
+    'zh-HANS': '质子束',
+    'zh-HANT': '質子束',
 };
 
 export const usingMockServer = process.env.DEEPL_MOCK_SERVER_PORT !== undefined;