The current study examines teenage sexual behavior (in terms of having had sexual intercourse) as a function of sexual attitudes and sexual efficacy. At the heart of the study lies the assumption that sexual attitudes such as permissiveness are related to sexual behavior, but that this relation is stronger for sexually efficacious teenagers than for others. Using longitudinal data from 253 British adolescents, a structural equation model is tested and fit. The results provide partial support for the expectations, demonstrating the usefulness of sexual efficacy in predicting sexual behavior. Limitations and implications of the study are discussed.