Congenital lung malformations are a heterogeneous group of abnormalities resulting from defective foregut specification, branching morphogenesis and cell proliferation, survival, and differentiation. Advancements in radiologic imaging and routine investigations in utero have resulted in a shift from postnatal to prenatal diagnoses. Prenatal diagnosis provides an opportunity to follow congenital malformations sequentially to better understand pathophysiological mechanisms. Genetic analysis of patients with hereditary lung malformations has also shed light on the molecular mechanisms underlying aberrant lung organogenesis. In this chapter, an overview of the five stages of lung development is given followed by discussion of the congenital lung malformations that result from defects in early and late lung morphogenesis. The malformations are described followed by a discussion of the associated syndromes, etiology, and pathogenesis with a focus toward the underlying cellular and molecular mechanisms. Clinical presentations, diagnosis, treatments, and outcomes are summarized, including radiographic and pathologic images of the most common malformations. The anomalies are presented in a format designed to provide clinicians caring for fetal and neonatal patients as well as scientists interested in lung development with a concise, up-to-date overview of congenital lung malformations and the deregulated cellular and molecular processes underlying their pathogenesis.