Résumé : Going beyond a narrow focus on social enterprise, Grimes, Williams, and Zhao (2019) advance a model of mission drift that they argue is relevant to understanding why—and with what consequences—all types of organizations might act in ways that are inconsistent with their identity and image. We applaud this effort, and agree that it is important to develop a theoretically rigorous approach to mission drift.Yet while the treatment that Grimes et al. (2019) develop is likely relevant to some organizations, their argument is built on a shakyfoundation, where “mission” is conceptualized in simplistic terms as an organization’s single, orienting purpose. In turn, this leads theauthors to make a number of problematic inferences about “drift” as a general phenomenon. This dialog details our concerns, and suggests thatit is vital to go upstream, and theorize mission as a nuanced and variegated construct if we are going to generate meaningful insightabout the nature, causes, and consequences of drift.