Background <p>Musculoskeletal disorders (MSDs) are a leading cause of global disability. This meta-analysis evaluated the efficacy of instrument-assisted soft tissue mobilization (IASTM) on pain, function, and range of motion (ROM) in patients with MSDs.</p> Methods <p>A systematic search was conducted across seven databases (PubMed, Embase, the Cochrane Library, PEDro, Web of Science, CNKI, and Wanfang Data) for RCTs on adult MSDs patients. Interventions included IASTM alone or as an adjunct to conventional rehabilitation; outcomes were pain, function, and ROM. The Cochrane RoB 2.0 tool assessed the risk of bias. Meta-analysis employed a random-effects model (RevMan 5.4, MATLAB-R2024), with subgroup analyses exploring heterogeneity by disease type, anatomical site, and intervention method.</p> Results <p>Twenty RCTs (<i>n</i> = 1420) were included. IASTM significantly reduced pain [SMD = − 0.84, 95% CI (− 1.07, − 0.61), <i>P</i> &lt; 0.00001] and increased ROM [SMD = 0.80, 95% CI (0.41, 1.18), <i>P</i> &lt; 0.0001]. The effect on function was marginal (SMD = − 0.48, <i>P</i> = 0.03). IASTM combined with conventional therapy showed more stable pain relief (<i>I</i>² = 22% vs. 85% for IASTM alone). Subgroup analyses indicated significant pain relief for lower limb (SMD = − 0.95) and spine disorders (SMD = − 0.89), and significant functional improvement for spine disorders only (SMD = − 1.02). ROM improvement was most consistent for spinal regions (SMD = 0.89, <i>I</i>² = 0%).</p> Conclusion <p>IASTM is effective for pain relief and improving ROM in MSDs, with enhanced stability when combined with conventional rehabilitation, particularly for lower limb and spinal conditions. The heterogeneous functional outcomes highlight the need for more sensitive assessment tools and standardized protocols.</p> PROSPERO ID <p>CRD420251117072.</p>