Lennox-Gastaut syndrome is a type of childhood epilepsy that has enormous detrimental effects on the patient's physical and developmental health and can also take a dramatic toll on the well-being of the patient's family. Lennox-Gastaut syndrome is characterized by variable etiology, multiple types of intractable seizures, and cognitive impairment in most patients. It is one of the most difficult epilepsy syndromes to treat and is frequently resistant to treatment with standard antiepilepsy drugs. This article reviews the etiology of Lennox-Gastaut syndrome, characteristics of predominant seizure types, methods of evaluating patients for Lennox-Gastaut syndrome, and available treatments including antiepilepsy drug therapy, ketogenic diet, and surgical options.