This systematic review and meta-analysis aimed to evaluate the effectiveness of psychological interventions compared to standard rehabilitation in patients with knee osteoarthritis (OA). Given the recognized influence of psychological factors in OA management, the review assessed their impact on pain, functional disability, and self-efficacy. A comprehensive search was performed across multiple databases, including PubMed, PsycINFO, CINAHL, the Cochrane Central Register of Controlled Trials, Web of Science, OpenGrey, and ClinicalTrials.gov, covering records from inception to September 2023. Eligible studies were randomized controlled trials that examined psychological interventions such as cognitive-behavioral therapy and biofeedback in adults with knee OA diagnosed based on established clinical or radiological criteria. Studies with mixed populations were included only if at least 75% of participants had OA. Exclusion criteria included studies focused on surgical patients or individuals with systemic conditions (e.g. rheumatoid arthritis). No restrictions were placed on intervention duration, allowing for a broad range of studies to be considered. From the 3,649 records identified, 70 studies met the inclusion criteria, and 20 studies involving 3,138 participants were included in the meta-analysis. The results demonstrated that psychological interventions led to significant improvements in pain (mean difference [MD]: -1.04; 95% confidence interval [CI]: -1.61 to -0.46), disability and function (standardized mean difference [SMD]: -0.26; 95% CI: -0.38 to -0.15), and self-efficacy (SMD: 0.49; 95% CI: 0.28 to 0.70). The strongest effects were observed in self-efficacy. However, concerns regarding methodological limitations, variability in intervention approaches, and high heterogeneity led to the evidence quality being rated as low to very low. This review underscores the potential benefits of psychological interventions in knee OA management, particularly for enhancing self-efficacy. Nonetheless, further high-quality research employing standardized protocols is needed to validate these findings and facilitate their clinical application.