The most prevalent joint disease is osteoarthritis (OA), which affects an estimated 240 million individuals worldwide. Knee osteoarthritis (KOA) is one of the top 10 causes of disability worldwide. The aim of this study is to systematically evaluate the effect of circuit training (CT) on patients with KOA. We searched through PubMed, Scopus, ScienceDirect, Cochrane, and Google Scholar up to 12 February 2022. We used random-effects statistical analysis for continuous variables and reported the results as a standardized mean difference (SMD) with 95 percent confidence intervals (CI). Seven trials involving 346 patients were included. A significant improvement in the intervention group was observed for the parameter, pain level (SMD -0.96, 95% CI -1.77 to -0.14; = 0.02; seven trials, 346 participants; high quality evidence), while no significant improvement was found in physical function (SMD 0.03, 95% CI -0.44-0.50; = 0.89; five trials, 294 participants; high-quality evidence), quality of life (SMD -0.25, 95% CI -1.18-0.68; = 0.60; three trials, 205 participants; high-quality evidence), the activity of daily living (SMD 0.81, 95% CI -0.85-2.48; = 0.34; three trials, 223 participants; high-quality evidence), and knee stiffness (SMD -0.65, 95% CI -1.96-0.66; = 0.33; two trials, 71 participants; high-quality evidence). The findings in this meta-analysis suggest that CT could effectively complement the conventional treatment of KOA, particularly in alleviating pain. However, comprehensive data on the guidelines for the CT approach would be needed to adequately examine the effects of CT on quality of life and biochemical markers in patients with KOA.