Social entrepreneurship has emerged as an active area of practice and research within the last three decades. Nevertheless, in spite of its growing popularity, scholars and practitioners are far from reaching a consensus as to what social entrepreneurship actually means. This has resulted in a number of different definitions and approaches within the field of social entrepreneurship. The purpose of this article is to shed light on the ongoing contestation of social entrepreneurship and to offer a novel conceptual understanding of the concept that can facilitate the development of systematic and structured future research. To this end, we analyze social entrepreneurship on the basis of the theory of essentially contested concepts, which was proposed by Walter Bryce Gallie in 1956. Building upon this theory, this article shows that social entrepreneurship can be regarded as an essentially contested concept and that a universal definition that would be accepted among contestant parties is hardly possible. Responding to this recognition, the article proposes the conceptualization of social entrepreneurship as a cluster concept, which can serve as a conceptual tool to help advancing social entrepreneurship as a coherent field of research despite its contested nature. •We show that social entrepreneurship is an essentially contested concept.•This implies that a single accepted definition is not possible.•Therefore, we propose a cluster concept understanding of social entrepreneurship.•A cluster concept understanding can facilitate systematic future research.