Circular RNAs (circRNAs) are covalently closed single-stranded RNAs without a 5' cap and 3' poly(A) tail, typically found in eukaryotic cells. They are mainly generated through back-splicing events in the nucleus. Initially considered non-coding, recent studies show that some circRNAs can be translated. This review highlights the 5' cap-independent internal initiation of translation on circRNAs. Key features include internal ribosome entry sites (IRESs), N6-methyladenosine (m6A) modification, and exon junction complexes (EJCs) near the back-splicing junction. The translatability of circRNAs is linked to their stability, with mechanisms like nonsense-mediated mRNA decay (NMD) and nonstop decay influencing this. Understanding circRNA translation expands proteomic knowledge. CircRNAs can be translated via IRESs, m6A modifications, or EJCs. They can also generate protein isoforms through various ORF arrangements. CircRNAs lacking stop codons may undergo rolling circle translation, producing multimeric proteins. The study emphasizes the need for further research into circRNA translation mechanisms and their biological implications.Circular RNAs (circRNAs) are covalently closed single-stranded RNAs without a 5' cap and 3' poly(A) tail, typically found in eukaryotic cells. They are mainly generated through back-splicing events in the nucleus. Initially considered non-coding, recent studies show that some circRNAs can be translated. This review highlights the 5' cap-independent internal initiation of translation on circRNAs. Key features include internal ribosome entry sites (IRESs), N6-methyladenosine (m6A) modification, and exon junction complexes (EJCs) near the back-splicing junction. The translatability of circRNAs is linked to their stability, with mechanisms like nonsense-mediated mRNA decay (NMD) and nonstop decay influencing this. Understanding circRNA translation expands proteomic knowledge. CircRNAs can be translated via IRESs, m6A modifications, or EJCs. They can also generate protein isoforms through various ORF arrangements. CircRNAs lacking stop codons may undergo rolling circle translation, producing multimeric proteins. The study emphasizes the need for further research into circRNA translation mechanisms and their biological implications.