Circular RNAs (circRNAs) are non-coding RNAs that are single-stranded and closed covalently. They are found in various organisms, from viruses to mammals. CircRNAs are involved in diverse biological processes, functioning as microRNA (miRNA) decoys and transcriptional modulators and interacting with RNA-binding proteins. Recent studies have shown that certain cytoplasmic circRNAs are capable of being translated into peptides. This discovery has shed light on the significance of circRNAs in cellular physiological processes. Moreover, there are several potential mechanisms for circRNA translation, including internal ribosome entry site (IRES)-driven translation and N6-methyladenosines (m6A)-mediated cap-independent translation. Thus, it indicates that circRNAs have a diverse role in regulating biological processes, particularly in various diseases. Furthermore, multiple studies have shown that circRNAs display unique expression patterns and play crucial roles in multiple diseases, suggesting their potential utility as diagnostic biomarkers and targets for therapeutic intervention.