**Abstract**

Asthma is a common and chronic inflammatory disease. The pathogenic mechanism underlying asthma is complex. Many inflammatory cells have been recognized as involved in asthma, containing lymphocytes (T, B cells), ILC2s, eosinophils, and other types of immune and inflammatory cells. It is well-established that allergen-specific Th2 cells play a central role in developing allergic asthma. In addition, in recent years, increasing studies have found that ILC2s can contribute to the pathogenesis of asthma by promoting the immune response of Th2 and secreting Th2 cytokines. MicroRNAs (MiRNAs and MiRs) is involved in immune inflammation and can induce excessive secretion of Th2 cytokines. The regulation of miRNAs to their targeting genes plays an important role in the development of asthma. This chapter has discussed altered expression and functions of miRNAs in Th2 and ILC2s in asthma, in order to better understand the mechanics of pathogenesis of asthma, and provide potential miRNA diagnostic indicators and therapeutic targets.

**Keywords:** asthma, Th2, ILC2s, cytokine, miRNAs
