diff --git a/openapi_python_client/templates/endpoint_module.py.jinja b/openapi_python_client/templates/endpoint_module.py.jinja
index 4db1c3546..d9645ce3d 100644
--- a/openapi_python_client/templates/endpoint_module.py.jinja
+++ b/openapi_python_client/templates/endpoint_module.py.jinja
@@ -51,13 +51,20 @@ def _get_kwargs(
         {% set destination = "_" + body.body_type + "_body" %}
         {{ body_to_kwarg(body, destination) | indent(8) }}
         _kwargs["{{ body.body_type.value }}"] = {{ destination }}
+        {% if body.content_type == "multipart/form-data" %}
+        headers["Content-Type"] = "multipart/form-data; boundary=+++"
+        {% else %}
         headers["Content-Type"] = "{{ body.content_type }}"
+        {% endif %}
+
 {% endfor %}
 {% elif endpoint.bodies | length == 1 %}
 {% set body = endpoint.bodies[0] %}
     {{ body_to_kwarg(body, "_body") | indent(4) }}
     _kwargs["{{ body.body_type.value }}"] = _body
-    {% if body.content_type != "multipart/form-data" %}{# Need httpx to set the boundary automatically #}
+    {% if body.content_type == "multipart/form-data" %}
+    headers["Content-Type"] = "multipart/form-data; boundary=+++"
+    {% else %}
     headers["Content-Type"] = "{{ body.content_type }}"
     {% endif %}
 {% endif %}