Sleep is increasingly being recognized as an important factor in the homeostasis of multiple body functions, including blood glucose metabolism. One of the most common sleep disorders, obstructive sleep apnea, is not only highly prevalent in patients with type 2 diabetes mellitus, but may contribute to the development of abnormalities in blood glucose metabolism. Evidence suggests that effectively treating sleep apnea, specifically with continuous positive airway pressure, improves glycemic and nonglycemic outcomes. Other common sleep disorders, such as insufficient sleep, shift work disorder, and restless legs syndrome, may also have a significant influence on the development and management of diabetes and its complications. The purpose of this article is to review the recent literature on the relationship between sleep disorders and blood glucose metabolism.