Organ fibrosis seriously threatens human health. Globally, more than 30% of the diseases that cause disability and death are due to organ fibrosis. However, there have been so far only a few effective treatments for organ fibrosis. Idiopathic pulmonary fibrosis (IPF) is progressive, lethal fibrotic lung disease. Approximately, 10/100,000 people globally suffer from pulmonary fibrosis, and the incidence is on the rise. The median survival for patients is only 3-5 years. Currently there is no effective treatment for lung fibrosis. Therefore, new insights into lung fibrosis and therapeutic strategy should be explored and developed. This Research Topic aims to deepen the understanding and research on the pathogenesis of lung fibrosis to develop effective treatments. Studies have shown that effective lung repair and regeneration are critical biological processes for the restoration of original physiological function of lung after injury. The intrinsic ability of regeneration and repair is often suppressed in lung with chronic injury or the diseased organs, leading to fibrosis and loss of function. Targeting key pathways in the process of lung regeneration can promote the repair of the impaired lung and alleviate fibrosis in animal models. How to induce regeneration and repair of the impaired organ to alleviate fibrosis is a frontier research topic. Hence, this Research Topic focuses on the cellular and molecular mechanisms of lung regeneration, repair, and fibrosis. Moreover, this topic will also focus on the study of lung development to provide new insights into the pathogenesis of lung injury and fibrosis.