N6-methyladenosine (m6A) plays a role in various diseases, but it has rarely been reported in acute lung injury (ALI). The fat mass and obesity-associated (FTO) protein can regulate mRNA metabolism by removing m6A residues. This study aimed to examine the role and mechanism of the m6A demethylase FTO in lipopolysaccharide (LPS)-induced ALI. Lung epithelial FTO knockout mice and FTO knockdown/overexpression A549 cell lines were constructed to evaluate the effects of FTO on ALI. Bioinformatics analysis and a series of in vivo and in vitro assays were used to examine the mechanism of FTO regulation. Rescue assays were conducted to examine whether the impact of FTO on ALI depended on the TXNIP/NLRP3 pathway. In LPS-induced ALI, RNA m6A modification levels were upregulated, and FTO expression was downregulated. In vivo, lung epithelial FTO knockout alleviated alveolar structure disorder, tissue oedema, and pulmonary inflammation and improved the survival of ALI mice. In vitro, FTO knockdown reduced A549 cell damage and death induced by LPS, while FTO overexpression exacerbated cell damage and death. Mechanistically, bioinformatics analysis revealed that TXNIP was a downstream target of FTO. FTO deficiency mitigated pyroptosis in LPS-induced ALI via the TXNIP/NLRP3 pathway. Rescue assays confirmed that the impact of FTO on the TXNIP/NLRP3 pathway was significantly reversed by the TXNIP inhibitor SRI-37330. Deficiency of FTO alleviates LPS-induced ALI via TXNIP/NLRP3 pathway-mediated alveolar epithelial cell pyroptosis, which might be a novel therapeutic strategy for combating ALI.