Much of the contemporary literature on headache disorders focuses on migraine headaches, despite the fact that tension-type headache (TTH) is highly prevalent and can be as debilitating as migraines. This article reviews the current literature on prevalence rates of psychiatric disorders in TTH populations, psychologic factors associated with TTH, and psychiatric disorders and their relationships with treatment outcomes in TTH. Key conclusions of this review include 1) prevalence rates of TTH vary across clinical and population-based samples; 2) greater TTH chronicity is associated with increased affective distress; 3) Axis II personality disorders may play an important role in TTH prevalence rates and psychologic functioning but have been understudied to date; and 4) maladaptive coping is common in persons with TTH.