Online group-buying business has existed in American and European online marketplaces since the late 1990s. Consumers with similar purchase interests are congregated on group-buying websites to obtain group discounts. In the last decade, group-buying business models have evolved to adapt to consumer needs, and a number of studies have offered several insights into how to improve online group-buying. This paper begins with a description of the global development of group-buying websites and an overview of the group-buying business models. Next, it provides a comprehensive overview of the existing literature in the online group-buying research field. Building on this review, the paper presents a meta-theoretical framework toward the sustainability of group-buying and provides research directions to guide future studies on online group-buying.