ZNF703, a member of the NET/Nlz family of zinc finger transcription factors, contributes to aspects of developmental growth and patterning across evolutionarily diverse species. ZNF703 has been identified as a novel oncogene in human breast cancer. In the present study, we investigated the expression of ZNF703 in gastric carcinoma and attempted to determine, using cell line models, its biological actions. Using immunohistochemistry, we analyzed the ZNF703 protein expression in 120 clinicopathologically characterized gastric cancer cases. Using RNA interference, we investigated the effects of ZNF703 depletion on tumor proliferation and metastasis in vitro. We found that ZNF703 was overexpressed in invasive gastric carcinoma tissues, and its expression levels were closely correlated with the depth of invasion, node metastasis and venous invasion. RNA interference-mediated silencing of the ZNF703 gene in SGC7901 cells inhibited cell proliferation and migration significantly. The results showed that ZNF703 acts as a gastric cancer oncogene and should be considered a therapeutic target for metastatic gastric cancer.