Although law was placed at the centre of the development process in the Law and Development movement launched in the 1960s, there was limited understanding at the time of the factors necessary for borrowed laws to succeed in the adopting country. This chapter investigates the theoretical links between adoption and implementation of borrowed competition laws and integrates strands from comparative law, literature on policy diffusion and transfer, and new institutional economics to develop a framework for examining competition law transplants as they proceed along the deliberation–adoption–implementation continuum. This chapter argues that a borrowed law may be considered successful if it is understood, utilised, and applied in the borrowing country and continues to grow in and become a part of its pre-existing legal system. It further argues that this is only possible if the borrowed law is compatible with the context of the adopting country and enjoys a degree of legitimacy in it.