Tension-type headache (TTH) is the most prevalent form of headache. Although it is not the most severe form of headache, it has a significant impact on society. In spite of this, little is known about its pathophysiology. Current International Headache Society classification has been called into question, and new classification approaches have been suggested. With reference to chronic TTH, the issue of analgesic rebound may confound the diagnosis. Transformed migraine and new persistent daily headaches are clarified and differentiated from chronic TTHs (CTTHs). The best documented abnormality found in TTHs is the presence of pericranial tenderness. It is generally believed that pain is initiated by a peripheral mechanism, most likely increased input from the myofascial nociceptors. In CTTH, there may be an impaired supraspinal modulation of the incoming stimuli. Whether there is an overlap in the continuum between TTH and migraine is controversial. Abortive and prophylactic treatments are discussed and wellness and adjunct therapy are also emphasized. Lastly, special attention is paid to the doctor-patient relationship in patients with difficult headaches.