This study examined the relationship between developmental assets during early and mid-adolescence and early adult sexual behaviors among American Indians using a subsample from the National Longitudinal Study of Adolescent Health (N = 465). Grounded in an assets framework, the authors explored the protective role of personal, family, school, and community assets as well as cumulative assets for sexual behaviors including early sexual debut, number of sexual partners, and frequency of condom use. The results indicated that certain assets during early and mid-adolescence, such as self-control, family support, and school attachment, were protective for various risky sexual behaviors in early adulthood. Furthermore, cumulative assets emerged as an important predictor of sexual behaviors. These findings highlight the utility of applying a developmental assets framework to understand protective factors among American Indian youth.