Backcasting has become a widely applied approach to address sustainability challenges when transformative changes are required. However, dispersed and contextualized knowledge of backcasting methodologies and practices needs to be systematized, codified, and synthesized to support researchers, commissioners, practitioners, and stakeholders in backcasting projects. In this paper, we address these issues by (i) concisely reviewing the evolution and current body of literature on backcasting and how this relates to other major types of futures and scenario studies and (ii) developing a design framework for researchers and practitioners that systematically covers all methodological choices with regard to key guiding questions to develop a backcasting methodology for a particular backcasting project. The developed design framework is based on four parts, characterized by the interrogatives when, which, how, and what, creating a comprehensive framework for describing a backcasting study.