For centuries, states were the only entities that produced norms. However, new forms of regulation that are neither hard law nor state-based, and not bound by territorial limitations, have emerged. Their impact is most profound in the financial sector, Information and Communication Technology, and Internet governance. This raises the question of how these new forms of regulation could impact WTO law: specifically, how private standards are being developed in the trade in services and how they may affect the application of the GATS and other services-related provisions. Additionally, the thesis explores to what extent WTO Members can be challenged for their possible use of such private standards as being disguised trade barriers. This thesis aims to raise awareness of the development of private standards in trade and services, and attempts to propose a new test where accountability and responsibility are attributed to States on the basis of such private standards.