The concepts of ‘scaling,’ ‘scalability,’ and ‘scale-up’ are increasingly used in business research and practice. However, the literature reveals a range of definitions for each, and often, their meanings are only implied. This diminishes the ability to build cumulative and meaningful insight - and conduct research - on each concept. In this editorial, we offer a systematic review that assesses and harmonizes prior definitions of these important concepts. This allows us to define and differentiate between (a) scaling as an organizational process, (b) scalability as an ordinary organizational capability, and (c) scale-up as a phase of organizational development. Complementing and extending existing scholarly work, we develop a rich agenda for scaling-related research in entrepreneurship.