Obsessive-compulsive disorder (OCD) is a debilitating condition that affects 1–4 percent of the child, adolescent, adult population, as well as, 8 percent of college athletes. Up to 25 percent of elite high school and professional athletes experience subthreshold obsessive-compulsive symptoms (Nazeer et al. Transl Pediatr 9(Suppl 1):S76–93, 2020; Cromer et al. Am J Psychiatry 174:6, 2017). This disorder presents with intrusive thoughts (obsessions) and distressing, time-consuming rituals (compulsions). The disorder can be chronic with periods of intense symptoms followed by periods of symptom relief, even if left untreated. It is paramount to make an early diagnosis due to the adverse sequelae of this disorder. Unfortunately, OCD is often underdiagnosed and undertreated. This chapter will review four cases that illustrate the importance of providing evidence-based treatment.