Although it is well known that different trauma histories can uniquely affect subsequent trauma-related symptoms, this is the first study to evaluate individual posttraumatic stress symptoms (PTSSs) in relation to trauma type and timing. This cross-sectional study surveyed a consecutive sample of mental health outpatients (n = 602), using regression to estimate associations between DSM-5 PTSSs and demographics, several trauma types, and age at first trauma in those with trauma (n = 367). Combat and sexual trauma were associated with worse total PTSS severity. Combat was significantly associated with arousal and intrusions (especially physical symptoms), sexual trauma with conscious avoidance and negative cognitions/mood (especially amnesia, an unconscious avoidance symptom), and physical assault with blame. Interpersonal traumas were the most common first traumas experienced, but age at first trauma was not significantly associated with PTSS severity. We discuss potential explanations and implications of these findings.