T helper 17 (Th17) cytokines are now widely believed to be critical for the regulation of various chronic immune diseases. Investigations have revealed a significant role for IL-17 cytokines in regulating inflammation and modulating lung and airway structural cells in asthma and COPD. In this review, our current understanding of the role of Th17-associated cytokines in airway diseases is summarized. Therapeutic approaches targeting IL-17 during asthma and COPD are also discussed.