Background and aims: Researchers have suggested that subtypes of problematic social media use (PSMU) should be identified for purposes of prevention and intervention. However, most studies have overlooked the heterogeneous characteristics of PSMU trajectories, and no research has systematically examined which interpersonal factors could predict these trajectories. In the present study, we identified classes of developmental trajectories of PSMU and examined differences across classes in adolescents? interpersonal functioning in family, school, and peer contexts. Methods: Participants were 357 Chinese adolescents enrolled in two middle schools in China (52.1% girls, aged 12-15 years). The students completed questionnaires in their classrooms over the course of one year in a three-wave longitudinal study. Results: Latent growth mixture modeling (LGMM) revealed three developmental trajectory classes of PSMU based on the intercepts and slopes of PSMU scores over time: high risk-gradual increase group (37%), low risk-sharp increase group (39%), and low risk-stable group (24%). Parent-adolescent attachment (family context), teacher-student relationships (school context), and deviant peer affiliation (peer context) were associated with variations in developmental trajectories. Conclusions: The findings can inform the design of prevention and intervention programs for specific subgroups of adolescents who show problematic social media use.  Kulcsszavak: problematic social media use, latent growth mixture modeling, interpersonal factors, adolescents