Gastric cancer is responsible for approximately one million annual deaths worldwide. Recently, the important roles of miRNAs as vital factors in malignancy processes such as metastasis have identified. They involve in the regulation of different biological procedures such as proliferation, invasion, metastasis and cell survival. MiR-146a has an aberrant expression in different tumors and has different expressions in the gastric cancer cell lines. This microRNA can act as a tumor suppressor and/or oncogene in gastric cancer related cases. Most of the studies have confirmed that miR-146a is downregulated in human gastric cancer cell lines and tissues, significantly and that it has tumor suppressor effects in gastric cancers. On the other hand, the role of miR-146a as an oncogene has been studied in an in-vitro experiment and results showed that over- an expression of miR-146a in gastric cancer tissues inhibits apoptosis and improves cell proliferation of gastric cancer cell. MiR-146a also has been a candidate for diagnosis and prognosis in gastric cancer cases. In this review, we focus on the important roles of miR-146a in tumor genesis of gastric tissues, emphasizing on the involvement of this microRNA in diagnosis, prognosis, chemotherapy response and finally, potential therapeutic applications as an anticancer agent in inhibition of gastric cancer cell metastasis and invasion.