diff --git a/end_to_end_tests/golden-record/my_test_api_client/api/tests/upload_file_tests_upload_post.py b/end_to_end_tests/golden-record/my_test_api_client/api/tests/upload_file_tests_upload_post.py
index 006d3c078..310b7bf43 100644
--- a/end_to_end_tests/golden-record/my_test_api_client/api/tests/upload_file_tests_upload_post.py
+++ b/end_to_end_tests/golden-record/my_test_api_client/api/tests/upload_file_tests_upload_post.py
@@ -20,7 +20,7 @@ def _get_kwargs(
     cookies: Dict[str, Any] = client.get_cookies()
 
     if keep_alive is not UNSET:
-        headers["keep-alive"] = keep_alive
+        headers["keep-alive"] = str(keep_alive).lower()
 
     multipart_multipart_data = multipart_data.to_multipart()
 
diff --git a/end_to_end_tests/golden-record/my_test_api_client/api/tests/upload_multiple_files_tests_upload_post.py b/end_to_end_tests/golden-record/my_test_api_client/api/tests/upload_multiple_files_tests_upload_post.py
index 5bcfc99c6..2cae2bdff 100644
--- a/end_to_end_tests/golden-record/my_test_api_client/api/tests/upload_multiple_files_tests_upload_post.py
+++ b/end_to_end_tests/golden-record/my_test_api_client/api/tests/upload_multiple_files_tests_upload_post.py
@@ -19,7 +19,7 @@ def _get_kwargs(
     cookies: Dict[str, Any] = client.get_cookies()
 
     if keep_alive is not UNSET:
-        headers["keep-alive"] = keep_alive
+        headers["keep-alive"] = str(keep_alive).lower()
 
     multipart_multipart_data = []
     for multipart_data_item_data in multipart_data:
diff --git a/openapi_python_client/__init__.py b/openapi_python_client/__init__.py
index a8860198e..8f7caa1fa 100644
--- a/openapi_python_client/__init__.py
+++ b/openapi_python_client/__init__.py
@@ -267,7 +267,9 @@ def _build_api(self) -> None:
             encoding=self.file_encoding,
         )
 
-        endpoint_template = self.env.get_template("endpoint_module.py.jinja")
+        endpoint_template = self.env.get_template(
+            "endpoint_module.py.jinja", globals={"isbool": lambda obj: obj.get_base_type_string() == "bool"}
+        )
         for tag, collection in endpoint_collections_by_tag.items():
             tag_dir = api_dir / tag
             tag_dir.mkdir()
@@ -281,7 +283,12 @@ def _build_api(self) -> None:
 
             for endpoint in collection.endpoints:
                 module_path = tag_dir / f"{utils.PythonIdentifier(endpoint.name, self.config.field_prefix)}.py"
-                module_path.write_text(endpoint_template.render(endpoint=endpoint), encoding=self.file_encoding)
+                module_path.write_text(
+                    endpoint_template.render(
+                        endpoint=endpoint,
+                    ),
+                    encoding=self.file_encoding,
+                )
 
 
 def _get_project_for_url_or_path(  # pylint: disable=too-many-arguments
diff --git a/openapi_python_client/templates/endpoint_macros.py.jinja b/openapi_python_client/templates/endpoint_macros.py.jinja
index 36c65d7e2..451ed1a51 100644
--- a/openapi_python_client/templates/endpoint_macros.py.jinja
+++ b/openapi_python_client/templates/endpoint_macros.py.jinja
@@ -2,10 +2,18 @@
 {% if endpoint.header_parameters %}
     {% for parameter in endpoint.header_parameters.values() %}
         {% if parameter.required %}
-headers["{{ parameter.name | kebabcase}}"] = {{ parameter.python_name }}
+headers["{{ parameter.name | kebabcase}}"] = {% if isbool(parameter) %}
+    str({{ parameter.python_name }}).lower()
+    {% else %}
+    {{ parameter.python_name}}
+    {% endif %}
         {% else %}
 if {{ parameter.python_name }} is not UNSET:
-    headers["{{ parameter.name | kebabcase}}"] = {{ parameter.python_name }}
+    headers["{{ parameter.name | kebabcase}}"] = {% if isbool(parameter) %}
+    str({{ parameter.python_name }}).lower()
+    {% else %}
+    {{ parameter.python_name}}
+    {% endif %}
         {% endif %}
     {% endfor %}
 {% endif %}