Résumé : The procedural justice model is a common framework for understanding how and why fair procedures conveyed by legal authorities (such as police officers) shape the legal socialization process. The present contribution draws upon self-determination theory (SDT) to advance the procedural justice model through its focus on internalization, in terms of identification and external regulation. Study 1 is a questionnaire-based study conducted among 268 Belgian adolescents that provides initial evidence for the incremental value of the SDT-based operationalization of internalization, above and beyond the classic operationalization (i.e., obligation to obey), for explaining why perceived procedural justice is linked to more compliance and less defiance. These results are corroborated in Study 2, which involves an experimental, vignette-based study (N = 210) contrasting a procedurally just versus unjust situation. The discussion focuses on how SDT may inform the legal socialization literature.