Messenger RNAs (mRNAs) contain prominent untranslated regions (UTRs) that are increasingly recognized to play roles in mRNA processing, transport, stability, and translation. 3' UTRs are believed to harbor recognition sites for a diverse set of RNA-binding proteins that regulate gene expression as well as most active microRNA target sites. Although the roles of 3' UTRs in the normal and diseased lung have not yet been studied extensively, available evidence suggests important roles for 3' UTRs in lung development, inflammation, asthma, pulmonary fibrosis, and cancer. Systematic, genome-wide approaches are beginning to catalog functional elements within 3' UTRs and identify the proteins and microRNAs that interact with these elements. Application of new data sets and experimental approaches should provide powerful insights into how 3' UTR-mediated regulatory events contribute to disease and may inspire novel therapeutic approaches.