This study explored factors that may be associated with early initiation of sexual activity among adolescents. Using the cumulative risk model, we hypothesized that as exposure to risk factors increases, so does the likelihood of early sexual debut. A sample of 273 (53% girls, 90% European American) adolescents was followed longitudinally from age 13 to 15. The results indicate that, for girls, increased television viewing, low self-esteem, poor parental relationships, living in a non-intact household, higher levels of externalizing behavior (ADHD symptomology), low academic achievement, and parents with low education levels were associated with earlier sexual debut. For boys, advanced pubertal development, increased television viewing, higher rates of externalizing behaviors (ADHD and ODD symptoms), and poor parental relationships were associated with earlier sexual debut. As hypothesized, predictive power increases with the accumulation of these risks; girls are 1.56 times more likely to become sexually active with an increase of only one risk and boys are 1.90 times more likely.