Sleep disturbances after a traumatic brain injury (TBI) have received very little scientific attention despite the fact that several studies indicate that they may occur in 30% to 70% of patients. For individuals with TBI, problems falling asleep or maintaining sleep can exacerbate other symptoms such as pain, cognitive deficits, fatigue, or irritability. Sleep disturbances can thus compromise the rehabilitation process and the ability to return to work. This article reviews the evidence on the epidemiology, etiology, and treatment of insomnia in the context of TBI and proposes areas for future research. Prevalence estimates of insomnia complaints in TBI patients are summarized. Potential etiological factors (i.e., lesions to the nervous system, anxiety) and possible consequences of insomnia (i.e., fatigue, cognitive problems) in the context of TBI are discussed. Finally, pharmacological and psychological treatments previously shown effective to treat insomnia in healthy individuals are discussed as valuable treatment options for TBI patients. Increased knowledge about the high prevalence, diagnosis, and potential etiological factors of insomnia following TBI may promote a better identification, evaluation, and treatment of sleeping difficulties in this population.