We examined the utility of the theory of reasoned action for predicting sexual intercourse among teenagers and determined whether it holds for both genders and for those with and without prior sexual experience. The data include 749 students who were in 9th–11th grades when the predictors were measured and in 10th–12th grades when sexual intercourse was assessed. About half (53%) were girls, about half (48%) were non-Hispanic European Americans. Results showed that prior sexual experience was related to a higher rate of sexual intercourse, but boys and girls did not differ. Tests of the causal model for subgroups (boy and girl virgins, boy and girl nonvirgins) yielded similar results. As predicted, paths from intentions to behavior and from norms and attitudes to intentions were significant, as were paths from outcome and normative beliefs to attitude and norm, respectively.