Growth mindsets are beliefs that abilities, like intelligence, are mutable. Although most prior work has focused on people's personal mindset beliefs, a burgeoning literature has identified that organizations also vary in the extent to which they communicate and endorse growth mindsets. Organizational growth mindsets have powerful effects on belonging and interest in joining organizations, suggesting that they may be a productive way to intervene to improve individual and societal outcomes. Yet, little is known about for whom organizational mindset interventions might be more or less effective, a critical question for effective implementation and theory. We examine whether people's personal mindset beliefs might determine the effect of organizational growth mindsets, and if so, whether this moderation reflects a matching or mismatching pattern. Three experiments manipulated the espoused mindset of an organization and found that organizational growth mindsets primarily increased belonging and interest in joining among participants who personally endorsed matching growth mindset beliefs. An additional field study provided ecological validity to these findings, replicating them with students' experiences of belonging in classrooms. This study also revealed a divergent mismatching pattern on grades: rather than bolstering the grades of students with growth mindsets, growth mindset classroom contexts primarily enhanced the grades of students with more fixed mindsets. By clarifying for whom organizational growth mindsets are beneficial and in what manner, the current work provides theoretical and practical insight into the psychological dynamics of organizational growth mindsets. (PsycInfo Database Record (c) 2023 APA, all rights reserved).