Licochalcone A (LicA), a flavonoid isolated from the famous Chinese medicinal herb Glycyrrhiza uralensis Fisch, has wide spectrum of pharmacological activities. In this study, the anti-cancer effects and potential mechanisms of LicA in non-small cell lung cancer (NSCLC) cells were studied. LicA decreased cell viability and induced apoptosis in a dose-dependent manner in NSCLC cells. LicA inhibited lung cancer cells growth by blocking cell cycle progression at the G2/M transition and inducing apoptosis. LicA treatment decreased the expression of MDM2, Cyclin B1, Cdc2 and Cdc25C in H460 and A549 cancer cell lines. In addition, LicA induced caspase-3 activation and poly-ADP-ribose polymerase (PARP) cleavage, which displayed features of apoptotic signals. Furthermore, LicA increased the expression of endoplasmic reticulum (ER) stress related proteins, such as p-EIF2α and ATF4. These data provide evidence that LicA has the potential to be used in the treatment of lung cancer.