Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach, we conducted a systematic review of 58 public administration studies of organizational socialization. Organizational socialization is the process of mutual adaptation between an organization and its new members. Our findings demonstrate a growing but geographically disparate interest in this issue. Public administration studies contribute to this research area with novel insights into the determinants of organizational socialization and its effects on employees’ public service motivation, Eurocrats’ support of supranational institutions, person–organization fit, and differences in the socialization of male and female public employees. The review also shows that the effects of organizational socialization on the homogenization of employees’ attitudes should not be exaggerated, especially relative to other homogenizing factors such as attraction or selection effects. The reviewed articles are methodologically eclectic, with a recent but growing interest in longitudinal designs. There are also weaknesses in the operationalization of organizational socialization. We conclude with an agenda for future studies on organizational socialization in public administration research.