In this chapter, the extant literature on sexual behaviors that are considered excessive and problematic in both forensic and non-forensic populations is reviewed. Current perspectives regarding conceptualization, diagnosis, assessment, and treatment are also critically reviewed. Although excessive sexual behavior has been variously defined (e.g., sexual addiction, compulsive sexual behavior, sexual impulsivity), the term “hypersexual disorder” will be used throughout this review. As indicated below, features of hypersexual disorder are evident among paraphilic and normophilic sexual behaviors (i.e., sexual behaviors that are culturally sanctioned). This chapter is focused predominantly on culturally normative and excessive sexual behavior.