As an emerging minimally invasive endoscopic technique, unilateral biportal endoscopic spinal surgery (UBE) has the advantages of flexibility, a wide and clear field of view, and less soft tissue damage. However, there is insufficient clinical evidence and controversy regarding UBE for the treatment of lumbar spinal stenosis (LSS). This meta-analysis investigated the clinical efficacy and complications of UBE for the treatment of LSS.PubMed, Embase, Web of Science, and the Cochrane Library were searched as of June 1, 2021 to identify all published references on UBE for LSS. Only English-language studies with original reported data including at least 30 cases were considered for inclusion. Patient demographics,operative time,hospital stay, complications, visual analogue score (VAS), Oswestry disability index (ODI), and Macnab criteria were extracted. Quality assessment was performed using the Cochrane Collaboration Tool for randomized controlled trials and the Newcastle-Ottawa Scale for retrospective studies. Meta-analysis was performed using a random or fixed effect model based on heterogeneity.Thirteen studies including 586 patients with 607 operation levels were included. The mean one-level operative time, hospital stay, and follow-up were 61.10 min, 2.32 days, and 14.7 months, respectively. At the final follow-up, the mean VAS score for leg pain decreased from preoperative 7.23 to 1.83, the mean VAS score for back pain decreased from 6.30 to 1.95,and the mean Oswestry Disability Index significantly improved from 56.99 to 17.83. The average satisfied outcome (excellent/good; based on the Macnab criteria) was 86%. The overall complication rate was 5%, of which the most common complication was dural tear with an incidence of 2%, followed by epidural haematoma with an incidence of 1%, and the rest were nerve root injury, inadequate decompression, and postoperative headache.Based on the available clinical results and experience from current studies, UBE for LSS is a feasible and effective approach and a worthwhile choice for clinicians.However, complications associated with the procedure should also be taken seriously.Copyright © 2021. Published by Elsevier Inc.