Histone demethylase KDM2A has been reported to be dysregulated in lung cancer. However, its function in gastric cancer remains poorly understood. Here, it was found that the expression level of KDM2A was increased in gastric cancer tissues. Moreover, forced expression of KDM2A in gastric cancer cells promoted cell growth and migration, while the knockdown expression of KDM2A inhibited the tumorigenicity of gastric cancer cells. Mechanistically, KDM2A regulated the growth and motility of gastric cancer cells through downregulating the expression of programmed cell death 4 (PDCD4), a known tumor suppressor in the progression of gastric cancer. Taken together, our study suggested that upregulation of KDM2A was very important in the progression of gastric cancer, and KDM2A might be a promising therapeutic target.