diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 318a1f0f..56499bc8 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -113,7 +113,7 @@ function(gz_msgs_protoc)
     COMMAND Python3::Interpreter
     ARGS tools/gz_msgs_generate.py
       --protoc-exec "$<TARGET_FILE:${gz_msgs_protoc_PROTOC_EXEC}>"
-      --gz-generator-bin "$<TARGET_FILE:gz_msgs_gen>"
+      --gz-generator-bin "${GZ_MSGS_GEN_EXECUTABLE}"
       --generate-cpp "${gz_msgs_protoc_GENERATE_CPP}"
       --generate-ruby "${gz_msgs_protoc_GENERATE_RUBY}"
       --generate-ignition "TRUE"