Previous studies indicate that a college-student's leader self-efficacy (LSE) enhances the ability to be an effective leader. However, there is limited empirical evidence on the college experiential factors that develop students' LSE in Historically Black Institutions (HBIs). The purpose of this study is to adapt Astin's input-environment-outcome (I-E-O) model to identify the effects of college experiential variables (environment) on student LSE development (output) while controlling for precollege variables (input). Pre- and post-data were collected from 200 freshmen studying at two Historically Black Institutions and analyzed using the hierarchical multiple regression (HMR). The findings suggested that precollege LSE and college co-curricular leadership experiences significantly influence students' LSE development.