Results presented in this report showed that Wnt5a was able to increase the stemness of aldehyde dehydrogenase (ALDH) positive lung cancer stem cells with an enhanced capacity of cell proliferation, migration, invasion, and colony formation and inhibit cell apoptosis in both of lung adenocarcinoma A549 cells and cisplatin-resistant A549/DDP cells. The gene discussed is WNT5A; the disease is lung adenocarcinoma.