Using large-scale longitudinal data, this study sought to examine factors influencing two important student development outcomes in students with disabilities attending 4-year colleges and universities. Informed by Astin's Input-Environment-Outcome model and the interactional model of disability, this study investigated the effect of student characteristics (i.e., disability type, gender, mother's education level) and environmental factors (i.e., faculty encouragement and engagement in political discussion) on the development of academic ability and intellectual confidence in students' senior year of college. The comparison between two outcome models for students with learning disabilities and those with physical or sensory disabilities provided important educational implications. Results from the multiple regression analyses revealed that both student characteristics and environmental factors significantly affect student development, accounting for students' academic ability and intellectual confidence upon entering college. Institutional policy implications and educational interventions for college students with disabilities were also discussed.