Cluster headache causes severe unilateral temporal or periorbital pain, lasting 15 to 180 minutes and accompanied by autonomic symptoms in the nose, eyes, and face. Headaches often recur at the same time each day during the cluster period, which can last for weeks to months. Some patients have chronic cluster headache without remission periods. The pathophysiology of cluster headache is not fully understood, but may include a genetic component. Cluster headache is more prevalent in men and typically begins between 20 and 40 years of age. Treatment focuses on avoiding triggers and includes abortive therapies, prophylaxis during the cluster period, and long-term treatment in patients with chronic cluster headache. Evidence supports the use of supplemental oxygen, sumatriptan, and zolmitriptan for acute treatment of episodic cluster headache. Verapamil is first-line prophylactic therapy and can also be used to treat chronic cluster headache. More invasive treatments, including nerve stimulation and surgery, may be helpful in refractory cases.