The main behavioral treatment suggestion today for headache management is the prevention of headaches mostly via avoidance of external and internal headache triggers. Despite the wide use of avoidance in headache management, very little empirical evidence exists to support its effectiveness. Attempts at avoiding headache triggers or other internal private experiences associated with a headache, may increase trigger potency, restrict lifestyle, decrease internal locus of control, and exacerbate and maintain pain perception. New treatment approaches, such as Acceptance and Commitment Therapy (ACT), emphasize acceptance and valued living as alternatives to avoidance. Though ACT is an empirically supported treatment for chronic pain, there is limited evidence for its efficacy for head pain, and this evidence is afflicted with methodological limitations that need to be overcome before making conclusions as to the effectiveness of ACT for headaches. The purpose of the present study is to examine in a Randomized Controlled Trial (RCT) whether an ACT-based intervention for headache sufferers, added to Medical Treatment as Usual, decreases disability and improves the quality of life, compared to only Wait List Control (WL). Pre, post and 3-months group changes will be assessed. Patients participating in the ACT group will be monitored for a year period.