PURPOSE: The present systematic review investigated the efficacy of intra-articular hyaluronic acid (HA) viscosupplementation for hip osteoarthritis (OA) in patient-reported outcome measures (PROMs) and whether different molecular weights of HA are associated with different outcomes. METHODS: This study was conducted according to the 2020 PRISMA statement. In January 2025, PubMed, Web of Science, Google Scholar, and Embase were accessed. All the randomised controlled trials (RCTs) evaluating the efficacy of intra-articular HA injections in the hip for OA were included. RESULTS: Nine hundred and eighty-two patients (56% women, mean age 62.2 ± 4.0 years, mean follow-up 6.4 ± 2.7 months, mean BMI 27.5 ± 2.1 kg/m) were analysed. Patients receiving high molecular weight (HMW) and low molecular weight (LMW) HA showed significant improvements in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and visual analogue scale (VAS) scores (P < 0.05). No significant differences in VAS or WOMAC were observed among groups at 3-4 months of follow-up. However, at 4-6 months, the HMW HA group exhibited significantly lower VAS scores compared to the medium molecular weight (MMW) (mean difference, MD - 1.4, 95% CI - 2.1 to - 0.7, P < 0.0001), placebo (MD - 1.6, 95% CI - 2.1 to - 1.1, P < 0.0001), and control (MD - 1.3, 95% CI - 1.8 to - 0.8, P < 0.0001) groups. WOMAC scores at 4-6 months demonstrated that both HMW and MMW HA performed better than the control group (P < 0.0001), but no significant difference was observed between HMW and MMW (P = 1.0). CONCLUSION: Intra-articular injections of HA effectively reduce knee OA symptoms. Moreover, HMW HA performs better than MMW HA at a mean of 4-6 months of follow-up. LEVEL OF EVIDENCE: Level I, systematic review of RCTs.