Over the past several decades, our knowledge of RNAs has increased dramatically. In particular, the recent advances in next-generation sequencing, combined with crosslinking immunoprecipitation or other variants, has led to the expansion of a list of RNAs including long noncoding RNAs (lncRNAs) and small regulatory RNAs such as microRNAs, short interfering RNAs, and Piwi-interacting RNAs. Although only a small number of previously unappreciated RNA roles have begun to be revealed, it is a good time to introduce the recent RNA advances and their related functions to readers. This special issue on RNA invites three perspectives, five mini-reviews, and four research articles. The topics covered in this special issue include microRNA-mediated gene silencing, the molecular mechanism of nonsense-mediated mRNA decay (NMD), mRNA translation, mitochondrial noncoding RNA (ncRNA) transport, genome-wide analysis of ncRNAs, and alternative polyadenylation.