Objectives To compare successes and complications of XEN GEL Stent implantation and gonioscopy-assisted transluminal trabeculotomy (GATT) surgery in patients with open-angle glaucoma (OAG). Methods The multicentre, non-randomized, comparative, interventional, retrospective chart review study included 114 eyes undergoing XEN implantation and 107 eyes undergoing GATT for treatment of OAG. A comprehensive ophthalmic examination consisting of best-corrected LogMAR visual acuity (BCVA), Goldmann Applanation Tonometry, biomicroscopy, fundoscopy and gonioscopy was performed, and then, clinical findings, complications and number of antiglaucomatous medications were noted at the 3-, 6-, 12-, 18- and 24-month postoperative visits. Surgical success was defined as IOP <= 21 mmHg and 20% >= IOP reduction from baseline with (qualified success) or without (complete success) further medication, and without any further IOP-lowering surgery. Results The mean ages were 65.8 +/- 10.6 and 59.1 +/- 14.3 in XEN and GATT groups, respectively (p = 0.001). In XEN group, the percentage of IOP reduction and need of medication were significantly more improved than those in GATT group. The complete surgical success rates were 34.2% and 50.5% in XEN and GATT groups, respectively (p = 0.039), with a success rate of 41.1% in total. Qualified surgical success rates were 97.4% and 89.7% in XEN and GATT groups, respectively (p = 0.025), with a success rate of 93.7% in total. Transient hyphema, the most observed postoperative complication in both groups, cleared in a few days. Conclusions Both MIGS have good efficacy and safety outcomes in lowering IOP and need of medication in patients with OAG. XEN Gel Stent implantation may be preferred in patients with lower IOP values targeted.