Women and men are exposed to potentially traumatic events almost in equal frequency. However, there are differences in prevalence of types of traumatic experiences in women and men. More men than women are exposed to accidents, nonsexual assaults, combat or war, disasters, illness, unspecified injuries, and witnessing the death or injury of others. In contrast, more women experience sexual assault and childhood sexual abuse. This entry examines the gender (social) and sex (biological) differences in trauma- and stressor-related disorders, such as posttraumatic stress disorder (PTSD), particularly with regard to prevalence and incidence and physiological responses to trauma.