This article describes a program of research designed to yield a conceptually grounded, psychometrically sound instrument for assessing the incidence and prevalence of sexual harassment in the workplace. Following the specification of a theoretical framework that is consistent with both legal guidelines and psychological research, we review the development and evaluation of a three-dimensional model of sexual harassment (gender harassment, unwanted sexual attention, and sexual coercion). Based on this model, we describe the development of a revised version of the Sexual Experiences Questionnaire (SEQ; Fitzgerald et al., 1988). Following extensive pilot work, the instrument was field tested in a large regulated utility. Data from 448 employed women (professional, technical, clerical and blue collar workers) support the reliability of the scales, and confirmatory factor analysis in this new sample confirms the stability and generalizability of the theoretical model. Following a brief review of validity data recently reported in the literature, implications for further measurement improvements are discussed.