Sleep is an important factor influencing the activation of seizures and interictal discharges. Sleep may contribute to the activation of many seizures, increase the frequency of epileptiform discharges, altering their morphology and distribution. On the other hand, seizures may influence sleep, leading to sleep abnormalities in epileptic patients. This review summarizes the interactions between sleep and epilepsy, the influence of sleep on seizure disorders, and seizure-induced changes in sleep patterns.