Previous research has shown that individuals with Fetal Alcohol Spectrum Disorder (FASD) are more likely to be overrepresented in the criminal justice system (CJS) compared to those without FASD. Criminal justice encounters can involve a range of harmful sexual behaviours (HSB), as well as sexual offences, and FASD-impacted individuals may be more vulnerable to such encounters. To date, there has been no review of the evidence regarding FASD, HSB, and/or sexual offending. A systematic review was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA) guidelines to identify primary studies, case studies, or case law reviews that have explored FASD in relation to HSB and/or sexual offending. A total of 21 articles met the inclusion and exclusion criteria for this review. Thirteen of these papers were primary studies, and the remaining eight were case law reviews, with three also providing case studies. Despite evidence linking FASD to increased HSB and sexual offending, the results of this review highlight significant research gaps in how features of FASD may provide a context of vulnerability for engaging in such behaviours.