Sexual self-concept (SSC), or the self-evaluation of sexual feelings and behaviors, can influence various health outcomes, such as sexual risk taking and contraceptive use. Much of the research on SSC has been limited to highly specialized samples, and it is not yet widely present in the general social science literature, despite fundamental, far reaching implications of the construct. One likely limiting factor in broader examination of the SSC construct is the perceived complexity. Lack of availability of short measures makes assessment as part of larger batteries relatively impractical. The current study sought to establish the factor structure of a previously developed and validated 100-item, 20-facet measure of SSC (the Multidimensional Sexual Self-Concept Questionnaire, MSSCQ; Snell, 1998) and identify a brief measure suitable for regular inclusion in broader research paradigms. Using cross-validation within an existing online sample (N > 17,000), I performed initial exploratory work, estimating the factor structure of the full measure and identifying items for a short form, in 90% of the original sample (discovery N > 15,000), and subsequently performed confirmatory analyses in the remaining 10% (replication N > 1,500). The analytic approach was preregistered at https://osf.io/zgqvm/. Exploratory factor analysis (EFA) of the 20 facets suggested that a four-factor structure was present (RMSEA=0.077, TLI=0.88, mean loadings=0.7). I then chose the highest loading items from one-factor confirmatory factor analyses (CFA) within each of the four factors and identified a short form with 16 items (four per factor) with good psychometric properties from item response theory (IRT) evaluations. We performed EFA on the final identified set of 16 items to confirm the maintenance of the four-factor structure in both the discovery sample as well as the set-aside independent replication sample (N > 1,500) I identified and replicated the structure of a short form measure of four factors of SSC in a large online sample. Future research will explore the overlap and differences between SSC and potentially related gender, sexuality, and personality constructs. The availability of an efficient assessment of SSC will allow a greater diversity of research into the development of this critically important, and yet historically under- investigated, identity construct.