The relation of psychosocial protective factors to involvement in problem behavior-alcohol and drug abuse, delinquency, and sexual precocity-was investigated in a longitudinal study of 7th-, 8th-, and 9th-grade adolescents in a large, urban school district. Protective factors were drawn from the personality, the perceived environment, and the behavior systems of problem-behavior theory. The findings show a significant inverse relation between protection and problem-behavior involvement. There is a significant interaction between protection and risk in the prediction of problem behavior: Protection is shown to moderate the relation of risk to problem behavior. Protective factors are also significant predictors of change in adolescent problem behavior over time. Direct effects of protection are consistent across all gender and racial/ethnic subgroups; moderator effects are evident for female, White, and Hispanic subgroups only.