ELMO3 is a member of the engulfment and cell motility (ELMO) protein family, which plays a vital role in the process of chemotaxis and metastasis of tumor cells. However, remarkably little is known about the role of ELMO3 in cancer. The present study was conducted to investigate the function and role of ELMO3 in gastric cancer (GC) progression. The expression level of ELMO3 in gastric cancer tissues and cell lines was measured by means of real-time quantitative PCR (qPCR) and Western blot analysis. RNA interference was used to inhibit ELMO3 expression in gastric cancer cells. Then, wound-healing assays, Transwell assays, MTS assays, flow cytometry, and fluorescence microscopy were applied to detect cancer cell migration, cell invasion, cell proliferation, the cell cycle, and F-actin polymerization, respectively. The results revealed that ELMO3 expression in GC tumor tissues was significantly higher than in the paired adjacent tissues. Moreover, knockdown of ELMO3 by a specific siRNA significantly inhibited the processes of cell proliferation, invasion, metastasis, regulation of the cell cycle, and F-actin polymerization. Collectively, the results indicate that ELMO3 participates in the processes of cell growth, invasion, and migration, and ELMO3 is expected to be a potential diagnostic and prognostic marker for GC.