Traumatic stress is a powerful moderator of physical and mental health outcomes. The impact of traumatic stress is visible across the lifespan from perinatal to late life stages of development. The biological mechanisms that drive symptom onset and expression have been the focus of intense study. Advances in neuroimaging and psychophysiology methods and applications now define clinical phenotypes that map onto biological indices. Treatment approaches that target specific cognitive, behavioral, and biological processes linked to traumatic symptoms show promise yet additional work is needed to optimize outcomes for individuals exposed to traumatic events.