<p>The aryl hydrocarbon receptor (AHR) is a transcription factor prominently expressed at barrier sites, while aldehyde dehydrogenase 3 family member A1 (ALDH3A1) is a metabolic enzyme implicated in oxidative stress. However, their roles in ferroptosis remain poorly understood. Imperatorin (IMP) is a bioactive compound derived from traditional Chinese medicine. Here, we demonstrate that IMP is a natural agonist of AHR, inhibiting LPS-induced ferroptosis, inflammation, and barrier damage in lung epithelial cells by promoting AHR nuclear translocation and activation. Mechanistically, IMP-activated AHR stimulated the Nrf2/HO-1/GPX4 axis and enhanced ALDH3A1 expression, thereby inhibiting ferroptosis-related Fe²⁺ accumulation, ROS production, and lipid peroxidation. The in vivo results showed that oral IMP activated the AHR/ALDH3A1 and Nrf2/HO-1/GPX4 pathways in lung tissue, thus improving lung dysfunction and inflammation in acute lung injury (ALI) mice induced by LPS. Notably, ALDH3A1 is a key downstream signaling protein of AHR. An AHR inhibitor reversed the IMP-induced upregulation of ALDH3A1, whereas an ALDH3A1 inhibitor blocked the anti-ferroptotic Nrf2/HO-1/GPX4 pathway and diminished the lung-protective effects of IMP-activated AHR both in vitro and in vivo. These findings indicate that the AHR/ALDH3A1 axis may represent a previously unrecognized therapeutic target for ferroptosis and provide insight into IMP as a therapeutic strategy to prevent and treat ALI.</p>