7 studies (6 RCTs and 1 CCT) that included a total of 314 patients with knee osteoarthritis (OA) were included in this meta-analysis and systematic review. The purpose of this review was to elucidate the efficacy of mesenchymal stem cell (MSC) injections in the treatment of knee OA by evaluating its effect on pain and function outcomes. While the findings of this study demonstrated potential efficacy for MSC injections for pain reduction and functional improvement that warrant further investigation, these findings were observed in a subgroup of higher quality studies or were associated with significant heterogeneity due to varying follow-up periods, doses of MSC and differing control groups. The low quality of evidence within the included trials limits the ability to draw conclusive results.