This paper examines the influence of the school environment on the likelihood that adolescent boys and girls will engage in unprotected sexual activity in Kenya. It also examines the relationship between premarital sex and pregnancy, as well as between pregnancy and school drop-out. It finds that, particularly for girls, a positive school environment can reduce the likelihood of participation in risky sexual activity. At the same time, however, it finds that pregnancy is the most common reason for drop-out among female Kenyan students.