<p>Bullying and victimization are common and problematic occurrences among disadvantaged children, yet little is known about the stability and changes in their bullying roles. Due to the chronic lack of family guardianship, de facto unattended children in China are a considerably disadvantaged population with limited social support and high risk of externalizing problems. Drawing on the social interactional continuity model and the ecological systems theory, the current study examined the profiles and transitions of bullying and victimization among Chinese de facto unattended children, along with their associated predictors. A total of 483 de facto unattended children completed self-report measures of bullying and victimization across two waves of the study over approximately 6 months. Multi-contextual risk and protective factors—including violence exposure, complex posttraumatic stress disorder (CPTSD) symptoms, and social support—were assessed at baseline. Latent profile analysis and latent transition analysis were employed for data analysis. The results revealed three profiles across the two time points (T1/T2): the uninvolved (72.5%/70.0%), severe-verbal victims (15.3%/21.5%), and bully-victims (12.2%/8.5%). The uninvolved showed the highest stability, whereas severe-verbal victims and bully-victims exhibited relatively high probabilities of mutual transition. Children with domestic violence exposure, greater CPTSD symptoms, and lower levels of school support were at higher risk of belonging to and transitioning to the involved groups. These findings systematically depict the heterogeneity and persistent risk patterns of bullying and victimization among Chinese de facto unattended children, offering insights for accurate identification of high-risk children. Accordingly, targeted interventions are recommended to focus on addressing CPTSD symptoms and enhancing school support.</p>