Objective: To explore the longitudinal relationship between bullying victimization and sleep quality among rural boarding junior high school students in Hebei Province, and to investigate the chain mediated role of loneliness and rumination, so as to provide evidence for promoting sleep health in the population. Methods: A baseline survey was conducted in May, 2023 (T1) by convenient sampling method, and two rounds of longitudinal surveys were conducted in November, 2023 (T2) and May, 2024 (T3) among students in two rural boarding junior high schools in Hebei Province, and a sample of 601 students who completed all the surveys was finally obtained. Students completed questionnaires, including the Delaware Bullying Victimization Scale Student (DBVS-S), the University of California at Los Angeles Loneliness Scale (UCLA), the Ruminative Responses Scale, and the Pittsburgh Sleep Quality Index (PSQI). Group differences were examined by using t-test or ANOVA, correlations between variables were analyzed by using Pearson correlation coefficients, and a serial mediation structural equation model was constructed, with mediation effects tested via the Bootstrap method. Results: Female students scored higher on sleep quality than male students (7.47±2.70, 6.47 ±2.46, t =4.74, P <0.01). Pearson correlation analysis indicated that bullying victimization was positively correlated with loneliness, rumination, and sleep quality; loneliness was positively correlated with rumination and sleep quality; and rumination was positively correlated with sleep quality ( r =0.26, 0.33, 0.23; 0.39, 0.38; 0.54, all P <0.01). Mediation analysis showed that T2 loneliness had an independent mediating effect of 0.70 (95% CI =0.36-1.35) between T1 bullying victimization and T3 sleep quality, T2 rumination had an independent mediating effect of 1.34 (95% CI =0.71-2.45), and the serial mediation effect of T2 loneliness and T2 rumination was 0.64 (95% CI =0.37-1.13), accounting for 22.11% of the total effect (all P <0.01). Conclusions Bullying victimization adversely affects sleep quality among rural boarding junior high school students through a longitudinal chain mediating pathway involving loneliness and rumination. Psychological interventions should be strengthened for students who experience bullying to alleviate their loneliness and reduce rumination, thereby improving sleep quality.