diff --git a/tests/renderers/test_hf.py b/tests/renderers/test_hf.py
index bcdd03c797..736478fbfa 100644
--- a/tests/renderers/test_hf.py
+++ b/tests/renderers/test_hf.py
@@ -11,6 +11,7 @@ from vllm.exceptions import VLLMValidationError
 from vllm.renderers.hf import (
     _consolidate_system_messages,
     _convert_developer_to_system,
+    _detect_content_format,
     _detect_developer_role_support,
     _get_hf_base_chat_template_params,
     _template_error_reason,
@@ -361,6 +362,66 @@ def test_resolve_chat_template_kwargs_with_template_name():
     assert "unknown_param" not in resolved
 
 
+@pytest.mark.parametrize(
+    ("chat_template", "expected_format"),
+    [
+        (
+            """
+            {% macro render_message(role, message_content) %}
+              {% for item in message_content %}{{ item['type'] }}{% endfor %}
+            {% endmacro %}
+            {% for message in messages %}
+              {{ render_message(message['role'], message['content']) }}
+            {% endfor %}
+            """,
+            "openai",
+        ),
+        (
+            """
+            {% macro render_message(role, message_content) %}
+              {% for item in message_content %}{{ item['type'] }}{% endfor %}
+            {% endmacro %}
+            {% for message in messages %}
+              {{ render_message(
+                  role=message['role'],
+                  message_content=message['content'],
+              ) }}
+            {% endfor %}
+            """,
+            "openai",
+        ),
+        (
+            """
+            {% for message in messages %}
+              {% for item in message['content'] %}{{ item['type'] }}{% endfor %}
+            {% endfor %}
+            """,
+            "openai",
+        ),
+        (
+            """
+            {% macro render_message(content) %}
+              {% for item in content %}{{ item['type'] }}{% endfor %}
+            {% endmacro %}
+            {% for message in messages %}
+              {{ render_message(content=['text only']) }}
+            {% endfor %}
+            """,
+            "string",
+        ),
+        (
+            """
+            {% for message in messages %}{{ message['content'] }}{% endfor %}
+            """,
+            "string",
+        ),
+    ],
+)
+def test_detect_content_format(chat_template, expected_format):
+    """Detect content format when content is passed through a macro."""
+    assert _detect_content_format(chat_template, default="string") == expected_format
+
+
 # NOTE: Qwen2-Audio default chat template is specially defined inside
 # processor class instead of using `tokenizer_config.json`
 @pytest.mark.parametrize(
@@ -373,9 +434,11 @@ def test_resolve_chat_template_kwargs_with_template_name():
         ("fixie-ai/ultravox-v0_5-llama-3_2-1b", "string"),
         ("Qwen/Qwen2-Audio-7B-Instruct", "openai"),
         ("meta-llama/Llama-Guard-3-1B", "openai"),
+        ("XiaomiMiMo/MiMo-V2.5-Pro", "openai"),
     ],
 )
 def test_resolve_content_format_hf_defined(model, expected_format):
+    """Detect the chat template content format for built-in HF models."""
     model_info = HF_EXAMPLE_MODELS.find_hf_info(model)
     model_info.check_available_online(on_fail="skip")
 
diff --git a/vllm/renderers/hf.py b/vllm/renderers/hf.py
index 2ceb66ffef..268a9aa463 100644
--- a/vllm/renderers/hf.py
+++ b/vllm/renderers/hf.py
@@ -397,10 +397,46 @@ def _iter_nodes_assign_messages_item(root: jinja2.nodes.Node):
 
 
 def _iter_nodes_assign_content_item(root: jinja2.nodes.Node):
+    """Yield loops that iterate over message content or macro-bound content."""
     message_varnames = [
         varname for _, varname in _iter_nodes_assign_messages_item(root)
     ]
 
+    # Track macro parameters that receive message.content as an argument.
+    # Some templates pass message.content through a macro parameter whose
+    # name is not literally "content".
+    macro_content_params_by_loop: dict[int, set[str]] = {}
+    loops_in_macros: set[int] = set()
+    for macro_node in root.find_all(jinja2.nodes.Macro):
+        macro_param_names = {arg.name for arg in macro_node.args}
+        macro_content_params: set[str] = set()
+        for call_node in root.find_all(jinja2.nodes.Call):
+            if (
+                isinstance(call_node.node, jinja2.nodes.Name)
+                and call_node.node.name == macro_node.name
+            ):
+                for i, arg in enumerate(call_node.args):
+                    if i < len(macro_node.args) and any(
+                        _is_var_or_elems_access(arg, varname, "content")
+                        for varname in message_varnames
+                    ):
+                        macro_content_params.add(macro_node.args[i].name)
+                for kwarg in call_node.kwargs:
+                    if (
+                        isinstance(kwarg, jinja2.nodes.Keyword)
+                        and kwarg.key in macro_param_names
+                        and any(
+                            _is_var_or_elems_access(kwarg.value, varname, "content")
+                            for varname in message_varnames
+                        )
+                    ):
+                        macro_content_params.add(kwarg.key)
+
+        for loop_ast in macro_node.find_all(jinja2.nodes.For):
+            loops_in_macros.add(id(loop_ast))
+            if macro_content_params:
+                macro_content_params_by_loop[id(loop_ast)] = macro_content_params
+
     # Search for {%- for content in message['content'] -%} loops
     # or {%- for item in content -%} loops
     for loop_ast in root.find_all(jinja2.nodes.For):
@@ -412,10 +448,26 @@ def _iter_nodes_assign_content_item(root: jinja2.nodes.Node):
                 assert isinstance(loop_target, jinja2.nodes.Name)
                 yield loop_ast, loop_target.name
                 break
+        else:
+            macro_content_params_for_loop = macro_content_params_by_loop.get(
+                id(loop_ast)
+            )
+            if (
+                isinstance(loop_iter, jinja2.nodes.Name)
+                and macro_content_params_for_loop is not None
+                and loop_iter.name in macro_content_params_for_loop
+            ):
+                assert isinstance(loop_target, jinja2.nodes.Name)
+                yield loop_ast, loop_target.name
+                continue
 
-        if isinstance(loop_iter, jinja2.nodes.Name) and loop_iter.name == "content":
-            assert isinstance(loop_target, jinja2.nodes.Name)
-            yield loop_ast, loop_target.name
+            if (
+                id(loop_ast) not in loops_in_macros
+                and isinstance(loop_iter, jinja2.nodes.Name)
+                and loop_iter.name == "content"
+            ):
+                assert isinstance(loop_target, jinja2.nodes.Name)
+                yield loop_ast, loop_target.name
 
 
 def _try_extract_ast(chat_template: str) -> jinja2.nodes.Template | None: