N6-methyladenosine (m6A) is the most common modification on mammalian mRNA and has gained considerable attention in recent years as a key regulator of gene expression. RBM15 is an important component of the methyltransferase complex. Although its functions are increasingly being recognized, a comprehensive overview of its critical roles in cancer regulation and potential therapeutic relevance is still lacking. This review aims to summarize recent advances in RBM15 by outlining its physiological functions in normal organisms, detailing its biological roles in tumor regulation and discussing its potential clinical applications. This work highlights its potential as a therapeutic target in oncology.