Dry eye disease (DED) is often secondary to diabetes mellitus (DM). We explored the action of Wilms tumor 1-associated protein (WTAP) in DM-DED via lncRNA NEAT1 m6A methylation. DM-DED mouse models were treated with sh-WTAP/sh-NEAT1 plasmid, followed by assessment of corneal epithelial damage/histopathological changes. HCE-2 cells were exposed to hyperosmotic conditions to establish DED models and treated with oe-NEAT1/sh-NEAT1/sh-WTAP/nigericin (an NLRP3 inflammasome inducer). Cell viability/apoptosis were evaluated by CCK-8/TUNEL. The levels of WTAP/NEAT1/inflammatory factors/NLRP3 inflammasome- and apoptosis-related markers were determined. m6A modification was examined by MeRIP-qPCR and NEAT1 stability was also detected. DM-DED mice exhibited up-regulated WTAP/NEAT1 expression and severe corneal damage, whereas WTAP/NEAT1 knockdown alleviated inflammation/corneal damage. In hyperosmolarity-induced HCE-2 cells, NEAT1 aggravated inflammation and apoptosis, while NEAT1 knockdown suppressed NLRP3 inflammasome activation and ameliorated cell injury. Hyperosmolarity-induced WTAP expression increased m6A modification and NEAT1 mRNA stability. WTAP mediated m6A methylation of NEAT1 and NLRP3 inflammasome activation in DM-DED mice. Collectively, WTAP upregulates NEAT1 expression and facilitates NLRP3 inflammasome activation by increasing m6A methylation, thereby accelerating DM-DED development. WTAP or lncRNA NEAT1 may become a therapeutic target for DM-DED, which offers a theoretical foundation for the investigation and advancement of nanocarrier-based targeted therapeutic medications for DM-DED.