An increasing number of organisations (e.g., Daimler, IBM and Red Hat) have adopted what has been called “open strategy”: involving large groups of people in strategy making via information technology (IT). Our review of the recently emerged research stream on open strategy reveals inconsistencies in the use of explicit definitions and implicit conceptualisations of open strategy. To support future discourse and research, we develop a theoretically coherent and comprehensive conceptualisation of open strategy as a practice in this paper. This conceptualisation is based on a structured review of existing publications and re-analysis of well-documented open strategy cases. We use the strategy-as-practice lens and the concept of Idealtypus as theoretical foundations. The paper proposes a research agenda for open strategy.