International audienceMost research suggests that nonprofit organizations (NPOs) should professionalize in order to become more efficient. Yet, a growing body of literature emphasizes the importance of preserving some of their original grassroots culture. Based on a qualitative meta-analysis of 19 in-depth cases from the past decade, our integrative model contributes to this debate in three important ways: first, we suggest that most NPO pathways of development are characterized by the acquisition of a dual nature i.e., a community setting a value-based mission (stage 1) and a professional structure involving formal and centralized coordination aimed at effectiveness (stage 2); second, that this dual system often leads NPOs to an existential crisis characterized by contradiction and indetermination (stage 3); and third, that this indetermination constitutes a window of opportunity for deciders to more deliberately arbitrate the orientation adopted by their NPOs (stage 4). We discuss the role of deciders, beyond institutional pressures, to explain why the nonprofit sector is still relatively diverse. We propose voluntarism and institutional entrepreneurship as important mainstays of nonprofitness