PURPOSE The Wnt gene family encodes the multifunctional signaling glycoproteins. We performed the present study to investigate the clinical significance of Wnt5a expression in non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS One hundred twenty-three patients with NSCLC who had undergone resection were investigated. Real-time quantitative reverse transcriptase polymerase chain reaction was performed to evaluate the Wnt5a gene expression. Immunohistochemistry was performed to investigate the Wnt5a protein expression, the Ki-67 proliferation index, tumor angiogenesis, and the expression of beta-catenin and vascular endothelial growth factor-A (VEGF-A). RESULTS Wnt5a gene expression in squamous cell carcinoma was significantly higher than that in adenocarcinoma (P < .0001). There was a significant correlation between the normalized Wnt5a gene expression ratio and the intratumoral Wnt5a protein expression (r = 0.729; P < .0001). The intratumoral Wnt5a expression was significantly correlated with the Ki-67 proliferation index (r = 0.708; P < .0001). In contrast, no correlation was observed between the intratumoral Wnt5a expression and tumor angiogenesis. Furthermore, the intratumoral Wnt5a expression was significantly correlated with the stromal expression of beta-catenin (r = 0.729; P < .0001) and VEGF-A (r = 0.661; P < .0001). In addition, the stromal VEGF-A expression was also correlated with Ki-67 proliferation (r = 0.627; P < .0001). Cox regression analyses demonstrated Wnt5a status to be a significant prognostic factor for NSCLC patients (P = .0193), especially for patients with squamous cell carcinomas (P = .0491). CONCLUSION The present study revealed that an overexpression of Wnt5a could produce more aggressive NSCLC, especially in squamous cell carcinomas, during tumor progression.