High-throughput RNA sequencing yields novel noncoding RNAs called circular RNAs (circRNAs). They are extensively distributed across the transcriptomes of humans and other metazoans. Research has demonstrated their critical functions in multiple cellular developmental processes and diseases, including cancer, cognitive disorders, and neurodegenerative disorders (NDDs). Aside from this, circRNAs carry out cellular functions by associating with RNA-binding proteins (RBPs) that are unique for each cell type. Given that they are a vast family of proteins, RBPs regulate gene expression through various processes like stabilization, localization, splicing, nuclear export, and RNA translation. The impact of circRNAs and the RBP complex on circRNA synthesis has become more apparent in recent years. As per new findings, circRNAs interact with RBPs and modify the way in which other RNAs and proteins operate. Numerous diseases are also linked to these relationships. Because of this, research regarding the circRNA and RBP relationship is crucial to comprehend the origins of a number of disorders. This chapter describes the newly discovered mechanisms underlying the interactions between circRNAs and RBPs as well as their functional significance in both illnesses and biological processes.