Sustained hyperglycemia is the basic feature of insulin resistance and type 2 diabetes. Disorders of glucose homeostasis lead to metabolic dysfunction, thus provoking diabetes and diabetic complications. Sirtuin 1 (Sirt1), a mammalian NAD-dependent protein deacetylase, plays a critical role in energy metabolism and insulin resistance. Recent studies suggest that activation of Sirt1 deacetylates various proteins such as PGC-1α, NF-κB, Foxo1 and Akt, which in turn protects pancreatic β cell functions, improves insulin sensitivity, attenuates inflammation and subsequently maintains glucose homeostasis. This review summarizes recent advances in the role of Sirt1 in regulating glucose homeostasis.