diff --git a/src/transformers/utils/chat_template_utils.py b/src/transformers/utils/chat_template_utils.py
index ee6173f2a1532b..414d2fb72454c5 100644
--- a/src/transformers/utils/chat_template_utils.py
+++ b/src/transformers/utils/chat_template_utils.py
@@ -80,7 +80,7 @@ def _parse_type_hint(hint: str) -> Dict:
             return_dict = subtypes[0]
         elif all(isinstance(subtype["type"], str) for subtype in subtypes):
             # A union of basic types can be expressed as a list in the schema
-            return_dict = {"type": [subtype["type"] for subtype in subtypes]}
+            return_dict = {"type": sorted([subtype["type"] for subtype in subtypes])}
         else:
             # A union of more complex types requires "anyOf"
             return_dict = {"anyOf": subtypes}
diff --git a/tests/utils/test_chat_template_utils.py b/tests/utils/test_chat_template_utils.py
index cff31c1f8a3483..1816ddd9512693 100644
--- a/tests/utils/test_chat_template_utils.py
+++ b/tests/utils/test_chat_template_utils.py
@@ -137,7 +137,7 @@ def fn(x: List[List[Union[str, int]]]):
                 "properties": {
                     "x": {
                         "type": "array",
-                        "items": {"type": "array", "items": {"type": ["string", "integer"]}},
+                        "items": {"type": "array", "items": {"type": ["integer", "string"]}},
                         "description": "The input",
                     }
                 },
@@ -455,13 +455,13 @@ def fn(
                     },
                     "y": {
                         "type": "array",
-                        "items": {"type": ["string", "integer"]},
+                        "items": {"type": ["integer", "string"]},
                         "nullable": True,
                         "description": "The second input. It's a big list with a single-line description.",
                     },
                     "z": {
                         "type": "array",
-                        "prefixItems": [{"type": ["string", "integer"]}, {"type": "string"}],
+                        "prefixItems": [{"type": ["integer", "string"]}, {"type": "string"}],
                         "description": "The third input. It's some kind of tuple with a default arg.",
                     },
                 },