The 14-3-3 protein has been shown to be involved in the cancer process. However, there is no understandingof the relationship between 14-3-3γ (14-3-3 gamma) expression and prognosis in advanced non-small cell lungcancer. In this study, we therefore investigated the association between protein levels by immunohistochemistryand clinicopathological features of advanced NSCLC patients. Survival curves were estimated using theKaplan-Meier method and tested by log-rank. Multivariate analysis was conducted with the Cox’s regressionmodel to determine independence of factors. p values less than 0.05 were considered significant. A total 153patients were studied, with 54.3% being stage III and 45.8% stage IV. Fifty-one cases (33.3%) were squamouscell carcinomas, and 98 cases (64.1%) were adenocarcinomas. High 14-3-3γ expression was seen in 59.5% andsignificantly correlated with lymph node metastasis (p=0.010) and distant metastasis (p=0.017). On Kaplan-Meieranalysis, high 14-3-3γ expression was associated with poorer survival with a marginal trend toward significance(p=0.055). On multivariate analysis, age, treatment, and 14-3-3γ expression proved to be independent prognosticparameters. In vitro experiments indicated that 14-3-3γ overexpression also played a potential role in cancerinvasion. In conclusion, our data suggest that 14-3-3γ overexpression is associated with invasion and a poorprognosis. Therefore, 14-3-3γ may be a potential prognostic marker of advanced non-small cell lung cancer.