INTRODUCTION: Intra-articular injections of ozone and hyaluronic acid (HA) are routinely performed for the management of knee osteoarthritis. The present meta-analysis compared intra-articular injections of HA versus ozone in patients with knee osteoarthritis (OA) in patient-reported outcome measures (PROMs). The outcomes of interest were to determine if intra-articular ozone injections show comparable visual analogue scale (VAS) and Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) scores compared to intra-articular HA injections. METHODS: This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses: the 2020 PRISMA statement. In January 2024, the following databases were accessed: PubMed, Web of Science, Google Scholar, and Embase. All the randomised controlled trials (RCTs) comparing intra-articular HA versus ozone injections in patients with knee OA were accessed. Only studies which clearly stated that injections were performed in patients with knee OA were considered. Data concerning the VAS and WOMAC were retrieved at baseline and the last follow-up. Studies with a follow-up shorter than 4 months or longer than 6 months were not included. RESULTS: Data from 424 patients were collected. 74% (314 of 424 patients) were women. The mean age of the patients was 61.1 ± 4.5 years, and the mean BMI was 27.8 ± 0.8 kg/m. Compatibility was found in the mean age, mean BMI, PROMs, and the percentage of women. No difference was found in VAS at follow-up (P = 0.4). CONCLUSION: The current level I evidence suggests that ozone and HA intra-articular injections achieve similar pain control between 4 and 6 months of follow-up. LEVEL OF EVIDENCE: Level I.