diff --git a/rosidl_generator_py/cmake/custom_command.cmake b/rosidl_generator_py/cmake/custom_command.cmake
index 5c9e9876..e2646d43 100644
--- a/rosidl_generator_py/cmake/custom_command.cmake
+++ b/rosidl_generator_py/cmake/custom_command.cmake
@@ -13,7 +13,7 @@
 # limitations under the License.
 
 add_custom_command(
-  OUTPUT ${_generated_extension_files} ${_generated_msg_py_files} ${_generated_msg_c_files} ${_generated_srv_py_files} ${_generated_srv_c_files}
+  OUTPUT ${_generated_extension_files} ${_generated_msg_py_files} ${_generated_msg_c_files} ${_generated_srv_py_files} ${_generated_srv_c_files} ${_generated_action_py_files} ${_generated_action_c_files}
   COMMAND ${PYTHON_EXECUTABLE} ${rosidl_generator_py_BIN}
   --generator-arguments-file "${generator_arguments_file}"
   --typesupport-impls "${_typesupport_impls}"
@@ -33,5 +33,7 @@ else()
     ${_generated_msg_c_files}
     ${_generated_srv_py_files}
     ${_generated_srv_c_files}
+    ${_generated_action_py_files}
+    ${_generated_action_c_files}
   )
 endif()
diff --git a/rosidl_generator_py/cmake/rosidl_generator_py_generate_interfaces.cmake b/rosidl_generator_py/cmake/rosidl_generator_py_generate_interfaces.cmake
index e10a5558..9fb15769 100644
--- a/rosidl_generator_py/cmake/rosidl_generator_py_generate_interfaces.cmake
+++ b/rosidl_generator_py/cmake/rosidl_generator_py_generate_interfaces.cmake
@@ -38,6 +38,8 @@ set(_generated_msg_py_files "")
 set(_generated_msg_c_files "")
 set(_generated_srv_py_files "")
 set(_generated_srv_c_files "")
+set(_generated_action_py_files "")
+set(_generated_action_c_files "")
 
 foreach(_typesupport_impl ${_typesupport_impls})
   set(_generated_extension_${_typesupport_impl}_files "")
@@ -47,6 +49,7 @@ foreach(_idl_file ${rosidl_generate_interfaces_IDL_FILES})
   get_filename_component(_parent_folder "${_idl_file}" DIRECTORY)
   get_filename_component(_parent_folder "${_parent_folder}" NAME)
   get_filename_component(_msg_name1 "${_idl_file}" NAME_WE)
+  get_filename_component(_ext "${_idl_file}" EXT)
   string_camel_case_to_lower_case_underscore("${_msg_name1}" _module_name)
 
   if(_parent_folder STREQUAL "msg")
@@ -65,6 +68,16 @@ foreach(_idl_file ${rosidl_generate_interfaces_IDL_FILES})
     list(APPEND _generated_srv_py_files
       "${_output_path}/${_parent_folder}/_${_module_name}.py"
     )
+  elseif(_parent_folder STREQUAL "action")
+    # C files generated for <msg>.msg, <service>_Request.msg and <service>_Response.msg but not <service>.srv
+    if(_ext STREQUAL ".msg")
+      list(APPEND _generated_action_c_files
+        "${_output_path}/${_parent_folder}/_${_module_name}_s.c"
+      )
+    endif()
+    list(APPEND _generated_action_py_files
+      "${_output_path}/${_parent_folder}/_${_module_name}.py"
+    )
   else()
     message(FATAL_ERROR "Interface file with unknown parent folder: ${_idl_file}")
   endif()
@@ -89,7 +102,15 @@ if(NOT _generated_srv_py_files STREQUAL "")
   )
 endif()
 
-if(NOT _generated_msg_c_files STREQUAL "" OR NOT _generated_srv_c_files STREQUAL "")
+if(NOT _generated_action_py_files STREQUAL "")
+  list(GET _generated_action_py_files 0 _action_file)
+  get_filename_component(_parent_folder "${_action_file}" DIRECTORY)
+  list(APPEND _generated_action_py_files
+    "${_parent_folder}/__init__.py"
+  )
+endif()
+
+if(NOT _generated_msg_c_files STREQUAL "" OR NOT _generated_srv_c_files STREQUAL "" OR NOT _generated_action_c_files STREQUAL "")
     foreach(_typesupport_impl ${_typesupport_impls})
       list(APPEND _generated_extension_${_typesupport_impl}_files "${_output_path}/_${PROJECT_NAME}_s.ep.${_typesupport_impl}.c")
       list(APPEND _generated_extension_files "${_generated_extension_${_typesupport_impl}_files}")
@@ -145,6 +166,12 @@ if(NOT _generated_srv_py_files STREQUAL "")
   get_filename_component(_srv_package_dir2 "${_srv_package_dir1}" NAME)
 endif()
 
+if(NOT _generated_action_py_files STREQUAL "")
+  list(GET _generated_action_py_files 0 _action_file)
+  get_filename_component(_action_package_dir1 "${_action_file}" DIRECTORY)
+  get_filename_component(_action_package_dir2 "${_action_package_dir1}" NAME)
+endif()
+
 if(NOT rosidl_generate_interfaces_SKIP_INSTALL)
   ament_python_install_module("${_output_path}/__init__.py"
     DESTINATION_SUFFIX "${PROJECT_NAME}"
@@ -167,6 +194,11 @@ if(NOT rosidl_generate_interfaces_SKIP_INSTALL)
       DESTINATION "${PYTHON_INSTALL_DIR}/${PROJECT_NAME}/${_srv_package_dir2}"
     )
   endif()
+  if(NOT _action_package_dir2 STREQUAL "")
+    install(FILES ${_generated_action_py_files}
+      DESTINATION "${PYTHON_INSTALL_DIR}/${PROJECT_NAME}/${_action_package_dir2}"
+    )
+  endif()
 endif()
 
 set(_target_suffix "__py")
@@ -179,7 +211,7 @@ file(WRITE "${_subdir}/CMakeLists.txt" "${_custom_command}")
 add_subdirectory("${_subdir}" ${rosidl_generate_interfaces_TARGET}${_target_suffix})
 set_property(
   SOURCE
-  ${_generated_extension_files} ${_generated_msg_py_files} ${_generated_msg_c_files} ${_generated_srv_py_files} ${_generated_srv_c_files}
+  ${_generated_extension_files} ${_generated_msg_py_files} ${_generated_msg_c_files} ${_generated_srv_py_files} ${_generated_srv_c_files} ${_generated_action_py_files} ${_generated_action_c_files}
   PROPERTY GENERATED 1)
 
 macro(set_properties _build_type)
@@ -203,6 +235,7 @@ set(_target_name_lib "${rosidl_generate_interfaces_TARGET}__python")
 add_library(${_target_name_lib} SHARED
   ${_generated_msg_c_files}
   ${_generated_srv_c_files}
+  ${_generated_action_c_files}
 )
 add_dependencies(
   ${_target_name_lib}
@@ -331,7 +364,9 @@ if(BUILD_TESTING AND rosidl_generate_interfaces_ADD_LINTER_TESTS)
     NOT _generated_extension_files STREQUAL "" OR
     NOT _generated_msg_c_files STREQUAL "" OR
     NOT _generated_srv_py_files STREQUAL "" OR
-    NOT _generated_srv_c_files STREQUAL ""
+    NOT _generated_srv_c_files STREQUAL "" OR
+    NOT _generated_action_c_files STREQUAL "" OR
+    NOT _generated_action_py_files STREQUAL ""
   )
     find_package(ament_cmake_cppcheck REQUIRED)
     ament_cppcheck(
diff --git a/rosidl_generator_py/resource/_msg.py.em b/rosidl_generator_py/resource/_msg.py.em
index 8a247963..86b59f60 100644
--- a/rosidl_generator_py/resource/_msg.py.em
+++ b/rosidl_generator_py/resource/_msg.py.em
@@ -43,11 +43,11 @@ class Metaclass(type):
             logger.debug(
                 'Failed to import needed modules for type support:\n' + traceback.format_exc())
         else:
-            cls._CREATE_ROS_MESSAGE = module.create_ros_message_msg_@(module_name)
-            cls._CONVERT_FROM_PY = module.convert_from_py_msg_@(module_name)
-            cls._CONVERT_TO_PY = module.convert_to_py_msg_@(module_name)
-            cls._TYPE_SUPPORT = module.type_support_msg_@(module_name)
-            cls._DESTROY_ROS_MESSAGE = module.destroy_ros_message_msg_@(module_name)
+            cls._CREATE_ROS_MESSAGE = module.create_ros_message_msg__@(subfolder)_@(module_name)
+            cls._CONVERT_FROM_PY = module.convert_from_py_msg__@(subfolder)_@(module_name)
+            cls._CONVERT_TO_PY = module.convert_to_py_msg__@(subfolder)_@(module_name)
+            cls._TYPE_SUPPORT = module.type_support_msg__@(subfolder)_@(module_name)
+            cls._DESTROY_ROS_MESSAGE = module.destroy_ros_message_msg__@(subfolder)_@(module_name)
 @{
 importable_typesupports = {}
 for field in spec.fields:
diff --git a/rosidl_generator_py/resource/_msg_pkg_typesupport_entry_point.c.em b/rosidl_generator_py/resource/_msg_pkg_typesupport_entry_point.c.em
index 21d12c48..fb22ec38 100644
--- a/rosidl_generator_py/resource/_msg_pkg_typesupport_entry_point.c.em
+++ b/rosidl_generator_py/resource/_msg_pkg_typesupport_entry_point.c.em
@@ -26,7 +26,7 @@ static_includes = set([
 for spec, subfolder in message_specs:
   if subfolder == 'msg':
     static_includes.add('#include <rosidl_generator_c/message_type_support_struct.h>')
-  elif subfolder == 'srv':
+  elif subfolder == 'srv' or subfolder == 'action':
     static_includes.add('#include <rosidl_generator_c/service_type_support_struct.h>')
 }@
 @[for value in sorted(static_includes)]@
@@ -61,21 +61,21 @@ module_name = convert_camel_case_to_lower_case_underscore(type_name)
 msg_typename = '%s__%s__%s' % (pkg_name, subfolder, type_name)
 }@
 
-static void * @(pkg_name)__@(module_name)__create_ros_message(void)
+static void * @(pkg_name)__@(subfolder)__@(module_name)__create_ros_message(void)
 {
   return @(msg_typename)__create();
 }
 
-static void @(pkg_name)__@(module_name)__destroy_ros_message(void * raw_ros_message)
+static void @(pkg_name)__@(subfolder)__@(module_name)__destroy_ros_message(void * raw_ros_message)
 {
   @(msg_typename) * ros_message = (@(msg_typename) *)raw_ros_message;
   @(msg_typename)__destroy(ros_message);
 }
 
 ROSIDL_GENERATOR_C_IMPORT
-bool @(pkg_name)__@(module_name)__convert_from_py(PyObject * _pymsg, void * ros_message);
+bool @(pkg_name)__@(subfolder)__@(module_name)__convert_from_py(PyObject * _pymsg, void * ros_message);
 ROSIDL_GENERATOR_C_IMPORT
-PyObject * @(pkg_name)__@(module_name)__convert_to_py(void * raw_ros_message);
+PyObject * @(pkg_name)__@(subfolder)__@(module_name)__convert_to_py(void * raw_ros_message);
 @[end for]@
 
 static PyMethodDef @(package_name)__methods[] = {
@@ -105,7 +105,7 @@ const rosidl_message_type_support_t *
 ROSIDL_GET_MSG_TYPE_SUPPORT(@(pkg_name), @(subfolder), @(spec.msg_name));
 
 int8_t
-_register_msg_type__@(type_name)(PyObject * pymodule)
+_register_msg_type__@(subfolder)__@(type_name)(PyObject * pymodule)
 {
   int8_t err;
 @[  for function_name in function_names]@
@@ -113,7 +113,7 @@ _register_msg_type__@(type_name)(PyObject * pymodule)
   PyObject * pyobject_@(function_name) = NULL;
   pyobject_@(function_name) = PyCapsule_New(
 @[    if function_name != 'type_support']@
-    (void *)&@(pkg_name)__@(type_name)__@(function_name),
+    (void *)&@(pkg_name)__@(subfolder)__@(type_name)__@(function_name),
 @[    else]@
     (void *)ROSIDL_GET_MSG_TYPE_SUPPORT(@(pkg_name), @(subfolder), @(spec.msg_name)),
 @[    end if]@
@@ -124,7 +124,7 @@ _register_msg_type__@(type_name)(PyObject * pymodule)
   }
   err = PyModule_AddObject(
     pymodule,
-    "@(function_name)_msg_@(type_name)",
+    "@(function_name)_msg__@(subfolder)_@(type_name)",
     pyobject_@(function_name));
   if (err) {
     // the created capsule needs to be decremented
@@ -144,15 +144,15 @@ function_name = 'type_support'
 
 ROSIDL_GENERATOR_C_IMPORT
 const rosidl_service_type_support_t *
-ROSIDL_TYPESUPPORT_INTERFACE__SERVICE_SYMBOL_NAME(rosidl_typesupport_c, @(spec.pkg_name), @(spec.srv_name))();
+ROSIDL_TYPESUPPORT_INTERFACE__SERVICE_SYMBOL_NAME(rosidl_typesupport_c, @(spec.pkg_name), @(subfolder), @(spec.srv_name))();
 
 int8_t
-_register_srv_type__@(type_name)(PyObject * pymodule)
+_register_srv_type__@(subfolder)__@(type_name)(PyObject * pymodule)
 {
   int8_t err;
   PyObject * pyobject_@(function_name) = NULL;
   pyobject_@(function_name) = PyCapsule_New(
-    (void *)ROSIDL_TYPESUPPORT_INTERFACE__SERVICE_SYMBOL_NAME(rosidl_typesupport_c, @(spec.pkg_name), @(spec.srv_name))(),
+    (void *)ROSIDL_TYPESUPPORT_INTERFACE__SERVICE_SYMBOL_NAME(rosidl_typesupport_c, @(spec.pkg_name), @(subfolder), @(spec.srv_name))(),
     NULL, NULL);
   if (!pyobject_@(function_name)) {
     // previously added objects will be removed when the module is destroyed
@@ -160,7 +160,7 @@ _register_srv_type__@(type_name)(PyObject * pymodule)
   }
   err = PyModule_AddObject(
     pymodule,
-    "@(function_name)_srv_@(type_name)",
+    "@(function_name)_srv__@(subfolder)_@(type_name)",
     pyobject_@(function_name));
   if (err) {
     // the created capsule needs to be decremented
@@ -185,7 +185,7 @@ PyInit_@(package_name)_s__@(typesupport_impl)(void)
 @{
 type_name = convert_camel_case_to_lower_case_underscore(spec.base_type.type)
 }@
-  err = _register_msg_type__@(type_name)(pymodule);
+  err = _register_msg_type__@(subfolder)__@(type_name)(pymodule);
   if (err) {
     Py_XDECREF(pymodule);
     return NULL;
@@ -195,7 +195,7 @@ type_name = convert_camel_case_to_lower_case_underscore(spec.base_type.type)
 @{
 type_name = convert_camel_case_to_lower_case_underscore(spec.srv_name)
 }@
-  err = _register_srv_type__@(type_name)(pymodule);
+  err = _register_srv_type__@(subfolder)__@(type_name)(pymodule);
   if (err) {
     Py_XDECREF(pymodule);
     return NULL;
diff --git a/rosidl_generator_py/resource/_msg_support.c.em b/rosidl_generator_py/resource/_msg_support.c.em
index 7d297951..d35754a0 100644
--- a/rosidl_generator_py/resource/_msg_support.c.em
+++ b/rosidl_generator_py/resource/_msg_support.c.em
@@ -61,16 +61,16 @@ msg_typename = '%s__%s__%s' % (spec.base_type.pkg_name, subfolder, spec.base_typ
 @[    if spec.base_type.pkg_name != field.type.pkg_name]@
 ROSIDL_GENERATOR_C_IMPORT
 @[    end if]@
-bool @(field.type.pkg_name)__@(lowercase_field_type)__convert_from_py(PyObject * _pymsg, void * _ros_message);
+bool @(field.type.pkg_name)__msg__@(lowercase_field_type)__convert_from_py(PyObject * _pymsg, void * _ros_message);
 @[    if spec.base_type.pkg_name != field.type.pkg_name]@
 ROSIDL_GENERATOR_C_IMPORT
 @[    end if]@
-PyObject * @(field.type.pkg_name)__@(lowercase_field_type)__convert_to_py(void * raw_ros_message);
+PyObject * @(field.type.pkg_name)__msg__@(lowercase_field_type)__convert_to_py(void * raw_ros_message);
 @[  end if]@
 @[end for]@
 
 ROSIDL_GENERATOR_C_EXPORT
-bool @(spec.base_type.pkg_name)__@(module_name)__convert_from_py(PyObject * _pymsg, void * _ros_message)
+bool @(spec.base_type.pkg_name)__@(subfolder)__@(module_name)__convert_from_py(PyObject * _pymsg, void * _ros_message)
 {
 @{
 full_classname = '%s.%s._%s.%s' % (spec.base_type.pkg_name, subfolder, module_name, spec.base_type.type)
@@ -146,7 +146,7 @@ lowercase_field_type = convert_camel_case_to_lower_case_underscore(field.type.ty
     @(nested_type) * dest = ros_message->@(field.name);
 @[      end if]@
     for (Py_ssize_t i = 0; i < size; ++i) {
-      if (!@(field.type.pkg_name)__@(lowercase_field_type)__convert_from_py(PySequence_Fast_GET_ITEM(seq_field, i), &dest[i])) {
+      if (!@(field.type.pkg_name)__msg__@(lowercase_field_type)__convert_from_py(PySequence_Fast_GET_ITEM(seq_field, i), &dest[i])) {
         Py_DECREF(seq_field);
         Py_DECREF(field);
         return false;
@@ -154,7 +154,7 @@ lowercase_field_type = convert_camel_case_to_lower_case_underscore(field.type.ty
     }
     Py_DECREF(seq_field);
 @[    else]@
-    if (!@(field.type.pkg_name)__@(lowercase_field_type)__convert_from_py(field, &ros_message->@(field.name))) {
+    if (!@(field.type.pkg_name)__msg__@(lowercase_field_type)__convert_from_py(field, &ros_message->@(field.name))) {
       Py_DECREF(field);
       return false;
     }
@@ -302,7 +302,7 @@ lowercase_field_type = convert_camel_case_to_lower_case_underscore(field.type.ty
 }
 
 ROSIDL_GENERATOR_C_EXPORT
-PyObject * @(spec.base_type.pkg_name)__@(module_name)__convert_to_py(void * raw_ros_message)
+PyObject * @(spec.base_type.pkg_name)__@(subfolder)__@(module_name)__convert_to_py(void * raw_ros_message)
 {
   /* NOTE(esteve): Call constructor of @(spec.base_type.type) */
   PyObject * _pymessage = NULL;
@@ -347,7 +347,7 @@ lowercase_field_type = convert_camel_case_to_lower_case_underscore(field.type.ty
 @[      else]@
       item = &(ros_message->@(field.name)[i]);
 @[      end if]@
-      PyObject * pyitem = @(field.type.pkg_name)__@(lowercase_field_type)__convert_to_py(item);
+      PyObject * pyitem = @(field.type.pkg_name)__msg__@(lowercase_field_type)__convert_to_py(item);
       if (!pyitem) {
         Py_DECREF(field);
         return NULL;
@@ -358,7 +358,7 @@ lowercase_field_type = convert_camel_case_to_lower_case_underscore(field.type.ty
     }
     assert(PySequence_Check(field));
 @[    else]@
-    field = @(field.type.pkg_name)__@(lowercase_field_type)__convert_to_py(&ros_message->@(field.name));
+    field = @(field.type.pkg_name)__msg__@(lowercase_field_type)__convert_to_py(&ros_message->@(field.name));
     if (!field) {
       return NULL;
     }
diff --git a/rosidl_generator_py/resource/_srv.py.em b/rosidl_generator_py/resource/_srv.py.em
index eab629ec..16756abb 100644
--- a/rosidl_generator_py/resource/_srv.py.em
+++ b/rosidl_generator_py/resource/_srv.py.em
@@ -31,19 +31,19 @@ class Metaclass(type):
             logger.debug(
                 'Failed to import needed modules for type support:\n' + traceback.format_exc())
         else:
-            cls._TYPE_SUPPORT = module.type_support_srv_@(module_name)
+            cls._TYPE_SUPPORT = module.type_support_srv__@(subfolder)_@(module_name)
 @{
 srv_name = '_' + convert_camel_case_to_lower_case_underscore(spec.srv_name)
 for field_name in [srv_name + '__request', srv_name + '__response']:
-    print('%sfrom %s.srv import %s' % (' ' * 4 * 3, package_name, field_name))
+    print('%sfrom %s.%s import %s' % (' ' * 4 * 3, package_name, subfolder, field_name))
     print('%sif %s.Metaclass._TYPE_SUPPORT is None:' % (' ' * 4 * 3, field_name))
     print('%s%s.Metaclass.__import_type_support__()' % (' ' * 4 * 4, field_name))
 }@
 
 
 class @(spec.srv_name)(metaclass=Metaclass):
-    from @(package_name).srv._@convert_camel_case_to_lower_case_underscore(spec.srv_name)__request import @(spec.srv_name)_Request as Request
-    from @(package_name).srv._@convert_camel_case_to_lower_case_underscore(spec.srv_name)__response import @(spec.srv_name)_Response as Response
+    from @(package_name).@(subfolder)._@convert_camel_case_to_lower_case_underscore(spec.srv_name)__request import @(spec.srv_name)_Request as Request
+    from @(package_name).@(subfolder)._@convert_camel_case_to_lower_case_underscore(spec.srv_name)__response import @(spec.srv_name)_Response as Response
 
     def __init__(self):
         raise NotImplementedError('Service classes can not be instanciated')
diff --git a/rosidl_generator_py/rosidl_generator_py/generate_py_impl.py b/rosidl_generator_py/rosidl_generator_py/generate_py_impl.py
index 6b0d20e3..2a87842a 100644
--- a/rosidl_generator_py/rosidl_generator_py/generate_py_impl.py
+++ b/rosidl_generator_py/rosidl_generator_py/generate_py_impl.py
@@ -98,7 +98,8 @@ def generate_py(generator_arguments_file, typesupport_impls):
     for subfolder in modules.keys():
         import_list = {}
         for module_name, type_ in modules[subfolder]:
-            if subfolder == 'srv' and (type_.endswith('Request') or type_.endswith('Response')):
+            if (subfolder == 'srv' or subfolder == 'action') and \
+               (type_.endswith('Request') or type_.endswith('Response')):
                 continue
             import_list['%s  # noqa\n' % type_] = 'from %s.%s._%s import %s\n' % \
                 (args['package_name'], subfolder, module_name, type_)