To evaluate the safety and efficacy of supraciliary stenting following failed glaucoma surgery. Interventional case series. Setting: Moorfields Eye Hospital, London, United Kingdom. Twenty eyes from 20 patients with glaucoma refractory to prior glaucoma surgery. Ab interno microstent (CyPass Micro-Stent; Alcon, Fort Worth, Texas, USA) implantation into the supraciliary space. Outcome measures included the occurrence of ocular adverse events, mean intraocular pressure (IOP) change, and glaucoma medication use through 12months. Mean baseline IOP was 22.5 ± 8.0mm Hg and number of medications was 2.7 ± 1.0. The majority of patients had undergone either prior trabeculectomy or aqueous shunt surgery. There were no serious intraoperative complications or major adverse events following supraciliary stenting. The most common adverse events included transient hyphema (3/20, 15%), transientIOP> 30mm Hg (4/20, 20%), and transient IOP<6mm Hg (4/20, 20%). At 12months, mean IOP was 14.9 ± 4.3mm Hg-a 33.7% reduction (P=.01). Mean medication usage decreased 56% to 1.2 ± 1.5 at 12months (P= .01). Two patients (10%) required subsequent aqueous shunt insertion. Ab interno supraciliary stenting has a favorable safety profile and provides an effective approach to controlling IOP and reducing medication burden in eyes in which previous glaucoma surgery has failed.