MicroRNAs (miRNAs) are small regulatory RNAs that bind directly to complementary sequences on target messenger RNA (mRNA) transcripts, resulting in translational repression and/or target mRNA degradation. MiRNAs have been proven to play critical roles on the development, differentiation, and function of immune cells. Regulatory T cells (Tregs) are of importance in maintaining immune homeostasis and self-tolerance. Although many transcription factors and cytokines are known to regulate Tregs, scientists began to focus on the role of noncoding RNA on the regulation of Treg cells. This review provides an overview of the entire microRNA network and specific miRNAs in the development, differentiation, and function of Tregs.