This cross-sectional study investigated self-esteem in relation to age, gender, ethnicity, and risk behaviors among a sample of nonmainstream students. Participants were 149 students in the 6th to 12th grades from two nonmainstream schools (one charter and one alternative school). Self-esteem and youth risk behaviors were determined by using a modified version of the Rosenberg Self-Esteem Scale (Rosenberg, 1965) and the National Alternative High School Youth Risk Behavior Survey (Grunbaum et al., 1999), respectively. Results indicated that nonmainstream students with high self-esteem were more likely to engage in their first sexual experience and to begin marijuana use later in life. African American students reported having their first sexual experience at an older age, but having more sexual partners than did Latino students. The implications of these findings are discussed.