The role of COL11A1 in carcinogenesis is increasingly recognized. However, the biological role and potential mechanisms of COL11A1 in gastric cancer have not been elucidated. In the present study, the COL11A1 mRNA expression in 57?patients with gastric cancer was measured by reverse transcription quantitative PCR (RT-qPCR), and the biological effects of COL11A1 suppression were determined using MTS, monolayer colony formation, flow cytometry and Transwell assays. In addition, the potential molecular mechanisms of COL11A1 in gastric cancer were analyzed by western blotting and cDNA microarray analysis. Compared with matched adjacent non-tumor tissue, COL11A1 mRNA was significantly overexpressed in tumor tissue and was positively related to age, tumor invasion depth, tumor size and lymph node positivity. Moreover, in?vitro experiments demonstrated that COL11A1 suppression by short hairpin RNA (shRNA) significantly inhibited the proliferation, migration and invasion of HGC-27 cells and that COL11A1 suppression promoted cell apoptosis, induced G1-phase cell cycle arrest and led to a significant downregulation of cyclin?D1 and upregulation of p21 and cleaved caspase-3. In addition, the cDNA microarray analysis of HGC-27 cells with and without COL11A1 suppression indicated that COL11A1 may regulate multiple genes responsible for cell growth and/or invasion, including downregulation of CDK6, TIAM1, ITGB8 and WNT5A and upregulation of RGS2 and NEFL following suppression of COL11A1 expression in HGC-27 cells, validated with RT-qPCR assays. Taken together, our findings demonstrate that COL11A1 might be an oncogene in GC and is a promising therapeutic target in cancer treatment.