Objectives: We sought to explore the association between childhood maltreatment (e.g., neglect, physical and sexual abuse) and longitudinal growth trajectories of body mass index (BMI) from adolescence to young adulthood. Methods: We used latent curve modeling to examine data from the National Longitudinal Study of Adolescent Health (N = 8,471), pooling years 1995-2008. Relative weight was indicated by BMI. Results: Children who experienced neglect had a faster average rate of BMI growth over time compared to children who experienced no childhood maltreatment. In addition, the co-occurrence of childhood neglect and physical abuse was related to increased levels of BMI at baseline, even after adjustment for 14 separate child and parental demographic and psychosocial characteristics. Parental obesity and education, child birth place, and family income were also associated with both baseline BMI and the rate of change in BMI over time. Conclusion: Childhood neglect plays a role in the development of adolescent obesity. Future research should examine potential mediators or moderators of the longitudinal relation between childhood neglect and adolescent and young adult obesity including impulsivity, depression, and compulsive eating behavior. (Contains 3 tables and 1 figure.)