To compare 5-year reoperation rates between Schlemm's canal (SC)-based glaucoma surgery and trabeculectomy (Trab), and to identify risk factors for reoperations.Retrospective case series.This retrospective study included patients who underwent glaucoma surgery between January 2017 and December 2021. Propensity score matching was used to identify comparable participants among groups. SC-based glaucoma surgery included gonioscopy-assisted transluminal trabeculotomy, microcatheter-assisted trabeculotomy, ab-interno canaloplasty, canaloplasty, and trabectome. The primary outcome was unanticipated reoperations after the original procedure. Kaplan-Meier survival analysis compared reoperation rates between groups. Univariate and multivariate Cox regression analyses identified risk factors for reoperation.The final analysis included 112 eyes (106 patients) in the SC-based glaucoma surgery group and 147 eyes (137 patients) in the Trab group. The 5-year cumulative reoperation rate was significantly higher in the Trab group compared to the SC-based glaucoma surgery group (15.4% [93/604] vs 11.9% [72/604], respectively, and p = 0.045). Uncontrolled intraocular pressure (IOP) was the primary indication for reoperations in both groups. Trab surgery, higher preoperative IOP, greater number of preoperative medications, and previous glaucoma surgery history were independent risk factors for reoperation.SC-based glaucoma surgery showed a significantly lower 5-year reoperation rate than Trab, indicating a more favourable long-term safety profile. Trab surgery, higher preoperative IOP, more preoperative medications, and previous glaucoma surgery history were identified as independent risk factors for reoperation, which may help identify patients at higher risk for reoperation and potentially improve postoperative management.Copyright © 2025 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.