A night terror, also known as pavor nocturnus, is a sleep disorder characterized by extreme terror and a temporary inability to regain full consciousness. The night terror is usually accompanied by gasping, moaning, or screaming. It is often impossible to fully awaken the person, and after the episode the victim normally settles back to sleep without waking.

Night terrors are distinct from nightmares in several key ways. First, the person is not fully awake when roused, and even when efforts are made to awaken the sleeper, they may continue to experience the night terror for over 10 or 20 minutes. Unlike nightmares, night terrors occur during the deepest levels of non-REM sleep. Furthermore even if awakened the victim can often not remember the episode except for a sense of panic, while nightmares are easily recalled.

Children from age four to six are most prone to night terrors, and they affect about three percent of all youngsters. Episodes may recur for a couple of weeks then suddenly disappear. They usually occur during the first couple of hours of sleep. Strong evidence has shown that a predisposition to night terrors can be passed genetically. Though there are a multitude of triggers, emotional stress during the previous day is thought to precipitate most episodes.

The consensus for treating night terror episodes is threefold: gentleness, disposal of anything nearby that might hurt the victim, and avoiding loud voices or movements that might frighten the victim further. Night terrors are so transitory that medical help is often unnecessary, but options may range from treatment of sleep apnea to prescription of benzodiazepines and psychotherapy.