This 3‐wave study investigated the developmental trajectories of nonsuicidal self‐injury (NSSI) and intrapersonal/interpersonal risk factors among 3,381 Chinese adolescents (56.2% females) aged from 13 to 17 years during a 1‐year period. Using an accelerated longitudinal design and latent class growth analysis, we identified four subgroups of NSSI trajectories: negligible (74.6%), experimental (12.8%), moderate decreasing (10.8%), and high fluctuating (1.9%). Adolescents reporting both intrapersonal (i.e., impulsive behaviors and depression) and interpersonal (i.e., unstable relationships and parental criticism) risk factors were significantly more likely to follow the latter three trajectories. The findings of this study suggest there is heterogeneity in NSSI development among adolescents and highlight the contributions of both intrapersonal and interpersonal risk factors in the engagement in NSSI.