Posttraumatic headache (PTHA) is, usually, one of several symptoms of the posttraumatic syndrome and therefore may be accompanied by somatic, psychological or cognitive disturbances. The aetiology of these symptoms in individuals with mild traumatic brain injury or whiplash injury has been a subject of some controversy with explanations ranging from neural damage to malingering. PTHA can resemble a tension-type headache, migrainous or cervicogenic headaches. Post-whiplash headache habitually is a pain radiating from the neck to the forehead, with moderate intensity and benign, but prolonged course. The pathogenesis of PTHA is still not well-known but might share some common headache pathways with primary headaches. In this chapter, we review recent investigations in the pathophysiology of PTHA, review recognised risk factors for a poor outcome and give some recommendations of management. We also discuss the new diagnostic criteria of IHS Classification, 2004, for PTHA and Headache attributed to whiplash.