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 2fe245b1..2810984c 100644
--- a/rosidl_generator_py/cmake/rosidl_generator_py_generate_interfaces.cmake
+++ b/rosidl_generator_py/cmake/rosidl_generator_py_generate_interfaces.cmake
@@ -17,23 +17,26 @@ find_package(rosidl_runtime_c REQUIRED)
 find_package(rosidl_typesupport_c REQUIRED)
 find_package(rosidl_typesupport_interface REQUIRED)
 
-# By default, without the settings below, find_package(Python3) will attempt
-# to find the newest python version it can, and additionally will find the
-# most specific version.  For instance, on a system that has
-# /usr/bin/python3.10, /usr/bin/python3.11, and /usr/bin/python3, it will find
-# /usr/bin/python3.11, even if /usr/bin/python3 points to /usr/bin/python3.10.
-# The behavior we want is to prefer the "system" installed version unless the
-# user specifically tells us othewise through the Python3_EXECUTABLE hint.
-# Setting CMP0094 to NEW means that the search will stop after the first
-# python version is found.  Setting Python3_FIND_UNVERSIONED_NAMES means that
-# the search will prefer /usr/bin/python3 over /usr/bin/python3.11.  And that
-# latter functionality is only available in CMake 3.20 or later, so we need
-# at least that version.
-cmake_minimum_required(VERSION 3.20)
-cmake_policy(SET CMP0094 NEW)
-set(Python3_FIND_UNVERSIONED_NAMES FIRST)
-
-find_package(Python3 REQUIRED COMPONENTS Interpreter Development NumPy)
+# Development gives Python3::Module, NumPy gives Python3::NumPy.
+if(NOT TARGET Python3::Module OR NOT TARGET Python3::NumPy)
+  # By default, without the settings below, find_package(Python3) will attempt
+  # to find the newest python version it can, and additionally will find the
+  # most specific version.  For instance, on a system that has
+  # /usr/bin/python3.10, /usr/bin/python3.11, and /usr/bin/python3, it will find
+  # /usr/bin/python3.11, even if /usr/bin/python3 points to /usr/bin/python3.10.
+  # The behavior we want is to prefer the "system" installed version unless the
+  # user specifically tells us othewise through the Python3_EXECUTABLE hint.
+  # Setting CMP0094 to NEW means that the search will stop after the first
+  # python version is found.  Setting Python3_FIND_UNVERSIONED_NAMES means that
+  # the search will prefer /usr/bin/python3 over /usr/bin/python3.11.  And that
+  # latter functionality is only available in CMake 3.20 or later, so we need
+  # at least that version.
+  cmake_minimum_required(VERSION 3.20)
+  cmake_policy(SET CMP0094 NEW)
+  set(Python3_FIND_UNVERSIONED_NAMES FIRST)
+
+  find_package(Python3 REQUIRED COMPONENTS Interpreter Development NumPy)
+endif()
 
 # Get a list of typesupport implementations from valid rmw implementations.
 rosidl_generator_py_get_typesupports(_typesupport_impls)