The current study investigated sexual initiations within the framework of the Theory of Planned Behavior (TPB) (Ajzen, 1991; Ajzen & Madden, 1986). Male and female daters in heterosexual dating relationships completed an online survey that assessed their sexual relationship with their partner and the TPB components (perceptions of social norms, attitudes, perceived behavioral control, and intentions). The TPB was supported for both men and women in that, as predicted, the more an individual perceived that important others would approve of them initiating sexual activities with their partner, the more positive their evaluations were of the outcomes of initiating, and the more confident they were in their ability to initiate, the stronger were their initiation intentions. In turn, stronger sexual initiation intentions were associated with more frequent initiation behaviors. Compared to women, men initiated more frequently, had stronger sexual initiation intentions, and perceived more positive social norms regarding initiation; men and women did not differ in their attitudes toward sexual initiation or in their perceived behavioral control. Both men and women who reported initiating more frequently and perceived their partner as initiating more frequently reported greater sexual satisfaction. These results are discussed in terms of the utility of the TPB for understanding sexual initiations and the role of the traditional sexual script in initiation-related cognitions and behavior.