In this article, we review basic research on sexual orientation for a clinical scientist-practitioner audience. We present contemporary and evolving approaches to defining and measuring sexual orientation, and we provide suggestions for how to translate psychological theory into best practices (i.e., how to select appropriate sexuality measures in both research and clinical settings). Our focus is on evaluating currently available measures of sexual orientation in terms of comprehensiveness and feasibility: How thoroughly are components of sexuality captured and how feasible it is to use such measures in research and clinical settings? Basic research in sexuality has progressed beyond our current clinical practices and should be used as a guide to more responsibly conceptualize participants and clients. While we determine that the current options are far from perfect, the critical clinician will find that contemporary measures of sexual orientation prove more useful than more simplistic predecessors. This review will elucidate best strategies for translating sexual orientation research and theory into clinical practice and provide clinicians and researchers alike with theoretically grounded support for tools of measurement and assessment. (PsycINFO Database Record (c) 2019 APA, all rights reserved).