Several studies have evaluated the effect of matrix metalloproteinase-9 (MMP-9) expression on the overall survival of patients with osteosarcoma, but the results remain conflicting. To examine the prognostic significance of MMP-9 expression in osteosarcoma risk, we conducted this meta-analysis to systematically review the published studies. We searched the commonly used electronic databases updated to September 2013 for relevant studies which evaluated the correction between MMP-9 expression and survival of patients with osteosarcoma. Overall, a total of eight studies including 437 cases were screened out. No significant heterogeneity was observed between studies. The MMP-9 was expressed in 73.9% (323/437) of cases, and the results showed that MMP-9 expression was associated with increased mortality rate of osteosarcoma during the follow-up (risk ratio = 2.79, 95% confidence interval, CI = 1.96-3.97, P < 0.00001). By ethnicity analysis, a significant correction was also found between MMP-9 expression and osteosarcoma risk among Asian and non-Asian population (P < 0.001), indicating that MMP-9 was an indicator of prognosis of osteosarcoma. In conclusion, this meta-analysis indicated that MMP-9 expression might be a biomarker of poor prognosis for patients with osteosarcoma. However, the prognostic value of MMP-9 on survival of osteosarcoma patients still needs further large-scale trials to be clarified.