Posttraumatic headache (PTH) affects millions of people annually. It is the most common presenting complaint of the postconcussion syndrome (see Chapter 15, Mild Brain Injury). PTH is defined as a new headache beginning after head or neck (and, presumably, brain) injury. Headache associated with brain injury usually is short-lived but may persist for months to years after the event. Acute PTH generally resolves within weeks. Here the important goals involve diagnosis of any treatable cerebral and/or neck pathology, including cervical spine fracture and intracranial hemorrhage. When PTH persists beyond 3 months, it is termed chronic PTH, and pain management and psychosocial issues become paramount. In this chapter we summarize important features of PTH disorders, including diagnosis, treatment, and prognosis.