The purpose of this study was to evaluate the main and interaction effects of PTSD and TBI on sleep outcomes in veterans. Post-deployment combat veterans ( = 293, 87.37% male) completed clinical interviews to determine diagnosis and severity of PTSD and deployment TBI history, as well as subjective measures of sleep quality, sleep duration, and restedness. Sleep-related medical diagnoses were extracted from electronic medical records for all participants. PTSD and TBI were each associated with poorer ratings of sleep quality, restedness, shorter sleep duration, and greater incidence of clinically diagnosed sleep disorders. Analyses indicated main effects of PTSD on sleep quality ( < .001), but no main effects of TBI. PTSD severity was significantly associated with poorer sleep quality ( < .001), restedness ( = .018), and shorter sleep duration ( = .015). TBI severity was significantly associated with restedness beyond PTSD severity ( = .036). There were no interaction effects between diagnostic or severity variables. PTSD severity is a driving factor for subjective ratings of sleep disturbance beyond PTSD diagnosis as well as TBI diagnosis and severity. Despite this, poor sleep was apparent throughout the sample, which suggests post-deployment service members may globally benefit from routine screening of sleep problems and increased emphasis on sleep hygiene.