Diabetes is a complex metabolic disease with an etiology that includes genetic, epigenetic and environmental factors that lead to several different defects of glucose homeostasis, primarily in the pancreatic β-cells, liver, muscle, and adipose tissues. MicroRNAs (miRNAs) have recently emerged as important regulators in post-transcriptional gene expression. Although the target genes and biological functions of individual miRNAs remain largely unknown, previous studies have shown them to be important regulators of diverse biological processes, in both normal and pathological states. In the past decade, an increasing number of studies have focused on the regulatory roles of miRNAs in metabolism; thus, miRNAs play an important role in the pathogenesis of diabetes. This review summarizes recent findings related to the roles of miRNAs in diabetes. The information presented herein might be useful for the future development of miRNAs as diagnostic and therapeutic targets in diabetes.