Lung cancer is a deadly cancer worldwide, and its pathogenesis and treatment methods require continuous research and exploration. As a representative factor of adaptive immunity, the role of interleukin-17A (IL-17A) in lung cancer is still unclear. The purpose of the present study was to investigate the effect of IL-17A on the biological behaviour of lung cancer cells and the relative mechanism. The human lung adenocarcinoma A549 and H1299 cell lines were used for in vitro study. The effects of IL-17A on cell proliferation, migration and invasion were assessed by CCK-8 assay, wound-healing assay, transwell invasion assay and real-time cell analysis (RTCA). The expression levels of marker proteins in the process of epithelial-mesenchymal transition (EMT) were detected by western blot analysis. Caspase-1 activity and the concentration of IL-1β after NLRP3 inflammasome activation were measured by a Caspase-1 Activity Assay Kit and an IL-1β ELISA kit, respectively. Compared to the control group, IL-17A treatment did not affect the proliferation of A549 and H1299 cells in vitro, but it promoted cell migration, invasion and the EMT process. IL-17A treatment increased NLRP3 expression, caspase-1 activity and IL-1β level. Blockade of NLRP3 alleviated the cell migration, invasion and the EMT process induced by IL-17A. In conclusion, these findings indicated that NLRP3 participates in the migration, invasion and the EMT process of IL-17A-stimulated lung cells in vitro.