<p>Parental psychological control has been linked to a rise in adolescent Internet gaming disorder (IGD). However, the influence of such control is shaped by ecological microsystems and family contextual factors, which remain insufficiently explored. The purpose of this study was to investigate how two microsystems—family and peers—jointly influence adolescent IGD, drawing on ecological systems theory and self-determination theory. Specifically, we examined peer victimization as a peer microsystem factor and the parent–adolescent relationship as a family context factor in the longitudinal pathway from parental psychological control to IGD. A total of 1,053 adolescents (mean age 11.43 ± 1.55 years, 540 males) completed questionnaires at three time points (T1, T2, T3, spanning 12 months with 6-month intervals). Based on this longitudinal design, a moderated mediation model revealed that parental psychological control at T1 predicted greater IGD at T3 via peer victimization at T2. Moreover, a high-quality parent–adolescent relationship amplified the effect of parental psychological control at T1 on peer victimization at T2, resulting in lower peer victimization in low psychological control and higher peer victimization in high psychological control. These findings highlight the importance of considering the complex dynamics between the parent–adolescent relationship and parenting styles in interventions for IGD.</p>