This chapter summarizes the current literature on post-traumatic stress disorder (PTSD) and chronic pain among military personnel in Canada, the United States, and the United Kingdom, including an overview of clinical features, prevalence, correlates, comorbidity, assessment, and intervention. PTSD and chronic pain are both prevalent among military populations and commonly co-occur; however, prevalence estimates tend to vary in the literature, according to type of assessment, timing of assessment, and subsample of interest. Both PTSD and chronic pain are independently associated with various adverse correlates such as psychiatric and physical health comorbidity, and research suggests there are poorer health and adverse psychosocial effects when these conditions co-occur. These findings highlight the importance of adequate prevention, screening, and interventions among this population.