Technology-driven payment instruments and services are facilitating the development of e-commerce; however, security concerns beleaguer their implementation, particularly in developing countries. This article considers the limits of private ordering in the regulation of e-payment systems. It uses Nigeria to exemplify a developing country that is increasingly pushing for the adoption of a regulatory framework for e-payment systems based on private ordering. It argues that, although technical standards and self-regulation by the financial industry are important, law is an essential regulatory mechanism that is largely absent. The article proposes that law be used as a mechanism to set and compel compliance with technical and industry standards, thus building trust, catering to public interest concerns and legitimizing the regulatory process.