A method, system and apparatus for extending an existing model-to-model transformation. A method for extending a model-to-model transformation can include merging an extension to the model-to-model transformation with the model-to-model transformation to produce an extended model-to-model transformation. Specifically, the merging step can include identifying insertion points for specified transform elements in the model-to-model transformation and inserting the specified transform elements at the identified insertion points in the model-to-model transformation to produce an extended model-to-model transformation. Subsequently, the extended model-to-model transformation can be dynamically applied to a source model in order to produce a target model.