Circular RNAs (circRNAs) are novel noncoding RNAs that play regulatory roles in gene expression. Dysregulation of circRNAs is associated with the development and progression of several diseases, such as diabetes mellitus, nervous system diseases, cardiovascular diseases, and cancer. CircRNAs functionally participate in cell physiological activities through various molecular mechanisms. However, these molecular mechanisms are unclear. Oxidative stress is an essential factor in the pathogenesis of various diseases, including neurological diseases. Emerging roles of circRNAs have been identified in different systems in response to oxidative stress. In this review, we summarize the current understanding of circRNA biogenesis, properties, expression profiles, and the clues indicating the regulatory roles of circRNAs through oxidative stress in various systems, especially the nervous system.