In addition to the well-known cognitive impairment following traumatic brain injury (TBI), neuropsychiatric sequelae are often reported as well. Although not the most common neuropsychiatric consequence of TBI, obsessive-compulsive disorder (OCD) has been associated with TBI. However, diagnosing new onset OCD secondary to TBI is complicated by the potential for cognitive impairment secondary to TBI masquerading as OCD. In particular, memory difficulties and executive dysfunction may be confused as representing obsessions and compulsions. Research in this area, which could guide clinical practice, remains limited. In addition to using Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V) criteria, neuropsychological testing and collateral interviews may help clinicians when considering differential diagnoses in this complex area of neuropsychiatry.