This article offers an overview of sexual behavior and contraceptive knowledge and use among adolescent women across a large number of developing countries. The results demonstrate that almost universally in sub-Saharan Africa and in the majority of countries in other regions, the gap between age at first sexual intercourse and age at first marriage has increased across age cohorts. The predominant pattern is one in which both age at marriage and age at first intercourse have risen, but the increase in age at marriage is greater, resulting in a widening gap. In most countries in sub-Saharan Africa, current contraceptive use is higher among sexually active, unmarried teens than it is among married teens, whereas in Latin America and the Caribbean, current-use levels are higher among married teens. The results also show that adolescents are unlikely to use a contraceptive the first time they have sex and are more likely than older women to experience a contraceptive failure.