Depression is a common mental disorder which leads to severe social dysfunction.Its exact pathophysiological mechanism is not fully explored,and there are no objective biomarkers for the diagnosis and treatment.Circular RNA is a kind of non-coding RNAs with closed circular structure.Because it is insensitive to RNase,it showed the advantages in being a biomarker for diseases.In recent years,an increasing number of studies have shown that circRNA plays a vital role in depression.This paper reviews the studies of circRNA in the development,diagnosis and treatment of depression,which might provide a valuable reference for future research.