Nocturnal leg cramps are a frequent cause of sleep disturbance among the general population, especially among the elderly. These painful episodes can delay sleep onset and awaken the patient from sleep, as well as delay subsequent return to sleep. Different mechanisms have been proposed to explain this phenomenon. Although most cases of leg cramps are idiopathic, multiple secondary causes of sleep-related leg cramps have been identified as well. In this article, we review the epidemiology, pathophysiology, and risk factors and discuss the salient features of the diagnosis and workup. Finally, we review the wide array of behavioral and pharmacologic treatments that have been studied for nocturnal leg cramps.