BackgroundOmega-3 polyunsaturated fatty acids (n-3 PUFAs) confers anti-inflammatory efficacy, which has been suggested to be effective for patients with osteoarthritis (OA). However, previous studies evaluating the influence of n-3 PUFAs supplementation in patients with OA showed inconsistent results. We performed a systematic review and meta-analysis to comprehensively evaluate the influence of n-3 PUFAs on symptom and joint function of patients with OA.MethodsRelevant randomized controlled trials (RCTs) were obtained by searching PubMed, Embase, and Cochrane Library databases. A random-effects model was employed to combine the results.ResultsNine RCTs with 2070 patients with OA contributed to the meta-analysis. Pooled results showed that n-3 PUFAs supplementation could significantly relieve the arthritis pain as compared to placebo (standardized mean difference [SMD]: − 0.29, 95% confidence interval [CI] − 0.47 to − 0.11,p= 0.002,I2= 60%). Besides, supplementation with n-3 PUFAs was also associated with improved joint function (SMD: − 0.21, 95% CI − 0.34 to − 0.07,p= 0.002,I2= 27%). Subgroup analysis showed consistent results of studies with arthritis pain and joint function evaluated by the Western Ontario-McMaster University Osteoarthritis Index and other scales (pfor subgroup difference = 0.33 and 0.34, respectively). No severe treatment-related adverse events (AEs) were observed in the included patients, and the incidence of overall AEs was similar between groups (odds ratio: 0.97, 95% CI 0.64–1.45,p= 0.86,I2= 0%).ConclusionsSupplementation of n-3 PUFAs is effective to relieve pain and improve joint function in patients with OA.