Fibroblast growth factor (FGF) signaling is known to play an important role in lung development. Our group recently demonstrated divergent effects in the role of certain FGF between mouse and human lung development. In this study, we identified FGF18, as an important FGF in human lung development. It favors branching and regulates multiple cellular and molecular events required for the maintenance of epithelial and mesenchymal progenitor cell pools, necessary for proper lung development.