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Sleep-related hypermotor epilepsy, previously known as nocturnal frontal lobe epilepsy, is a focal epilepsy with seizures arising from sleep, typically involving activation of ventromesial frontal, insular, or frontoparietal networks. The etiology may be genetic or due to structural pathology but in most cases is unknown. Seizures are characterized by hypermotor activity with violent proximal limb movements or tonic-dystonic posturing, usually short in duration and often in clusters during non–rapid-eye-movement (NREM) sleep and sleep/wake transitions. The differentiation of seizures from physiologically arousals or pathological arousals (NREM parasomnias) is often challenging, and misdiagnosis is common. Video electroencephalography-polysomnography recording typical events is often required to confirm the diagnosis.