This literature review is the first to summarize past research on e-commerce transformations and outline a research agenda to understand them. By bringing together concepts from institutional and organizational transformation theories, we develop a conceptual framework to analyze e-commerce transformations and their dynamics. We review 91 papers on e-commerce transformations published between 1995 and 2023 and assess them with our a priori framework to identify six underexamined areas. We then develop a corresponding research agenda and delineate two research thrusts to further our understanding of present and future e-commerce transformations. Our first research thrust calls for analyses of ecosystem-level pressures, regulatory frameworks, and the influence of new intermediaries on e-commerce transformations. Our second thrust proposes to investigate mechanisms that spread or impede forces of change within the organization.