This chapter introduces XML-based e-commerce standards that have emerged within the past decade. The chapter describes the history of e-commerce standards, and then presents representative horizontal and vertical e-commerce standards by detailing their functionality, and how their development has been shaped by various stakeholders. The chapter also describes the potential for these standards to transform B2B practice by providing three industry examples. The chapter finishes by suggesting directions for future research by describing factors that could influence the future of these standards. Due to the central role these standards are likely to play in future e-commerce activity, most firms will at some point need to become aware of their capabilities, their application, and potential impact. This chapter is intended to provide an overview of the situation as it is understood today, and presents likely scenarios for how these standards may progress.