Objective: To investigate the effect of interleukin 6 (IL-6) on the biological behaviors in gallbladder carcinoma cells and its association with JAK/STAT3 signaling pathway. Methods: The gallbladder carcinoma GBC-SD cells were treated with IL-6 orIL-6 plus AG490 (an inhibitor of JAK/STAT3 pathway); the cell proliferation and invasive ability, the matrix metalloproteinase 9 (MMP-9) activity, and protein expressions of the phosphorylated STAT3 (p-STAT3) and vascular endothelial growth factor (VEGF) in the cells were determined by MTT assay, Transwell migration assay, gelatin zymography and Western blot analysis, respectively. Results: The proliferation of GBC-SD cells was significantly increased in a concentration-dependent manner after treatment with IL-6 (10,50 and 100ng/mL), but the proliferative effect of IL-6 was abolished by AG490 treatment. Further, in GBC-SD cells after IL-6 treatment, the invasive ability and MMP-9 release were significantly elevated (both P<0.05), and both p-STAT3 and VEGF protein expressions were remarkably up-regulated, and all above effects of IL-6 were abolished by AG490. Conclusion: IL-6 can promote the growth and enhance the invasive ability of gallbladder cancer cells and these actions may be associated with its activation of the JAK/STAT3 signaling pathway, leading to the downstream MMP9 and VEGF expressions.