How people fit into social groups is a core topic of investigation across multiple sociological subfields, including education, immigration, and organizations. In this chapter, we synthesize findings from these literatures to develop an overarching framework for conceptualizing and measuring the level of cultural fit and the dynamics of enculturation between individuals and social groups. We distinguish between the cognitive and behavioral dimensions of fitting in, which previous work has tended to either examine in isolation or to conflate. Reviewing the literature through this lens enables us to identify the strengths and limitations of unitary—that is, primarily cognitive or primarily behavioral—approaches to studying cultural fit. In contrast, we develop a theoretical framework that integrates the two perspectives and highlights the value of considering their interplay over time. We then identify promising theoretical pathways that can link the two dimensions of cultural fit. We conclude by discussing the implications of pursuing these conceptual routes for research methods and provide some illustrative examples of such work.