The notion of generalizability has deep roots in models of reasoning and knowledge. It is a basic principle and core epistemic value of science and typically involves inferring or extrapolating research findings to external settings. Yet it remains a broad concept that applies to different elements of research. As such, it gives way to varying definitions and strategies for addressing it. In quantitative research traditions, generalizability of research findings is broadly accepted as a core principle and epistemic goal of empirical research. As such, “classical” forms of generalizability are emphasized. Generalizability has been a more contentious concept within qualitative research, with some researchers viewing it as “contrary to the goal” of qualitative research, others embracing alternative conceptions to the classical view. Debates have arisen on topics ranging from how to protect generalizability from “threats” to whether it ought to be a goal of research at all and, if so, how it might be reconceptualized to accommodate nontraditional forms of research.