The authors describe how Rest's (1986) model of ethical decisionmaking and behavior and Jones' (1991) construct of the moral intensity of an issue may be used as the basis for an ethical decisionmaking model of sexual harassment. The chapter also generates propositions consistent with an ethical perspective of sexual harassment and compares this model with other relevant theories of sexual harassment. The authors discuss the influence of the moral intensity of social-sexual behavior on observers' progression through the four stages of ethical decisionmaking and behavior. This is followed by an analysis of influences on observers' perceptions of the moral intensity of social-sexual behavior. Moderators of the relationships between observers' moral judgments, intentions, and behavior are also addressed. The authors advise that the ethical decisionmaking perspective offers unique insight into why different people consider some social-sexual behaviors but not other behavior as sexual harassment. This suggests classification of different types of social-sexual behavior according to their magnitude of consequences, temporal immediacy, probability of effect, and concentration of effect. 1 figure and 36 references