We aimed to determine the effect of semaglutide on patients with acute large vessel occlusion (LVO) receiving endovascular therapy (EVT). In this phase 2, investigator-initiated, multicenter, prospective, randomized, open-label, blinded endpoint trial conducted in China, we recruited patients with disabling LVO undergoing EVT. Patients were randomized to semaglutide therapy (0.5 mg subcutaneous semaglutide before and 1 week after EVT) or standard therapy. The primary outcome was defined as favorable neurological recovery (modified Rankin Scale 0–2 at 90 days). Between August 2023 and July 2024, 140 patients were randomized to semaglutide (n = 69) or standard therapy (n = 71). The primary outcome occurred in 39 (56.5%) in the semaglutide group and 39 (54.9%) in the standard therapy group (adjusted RR 1.05, 95% CI 0.95–1.15, p = 0.37). We observed treatment effect modification by intravenous thrombolysis (IVT) on semaglutide therapy (p_interaction = 0.02); thus we performed the following exploratory analyses: The primary outcome occurred in 22 (64.7%) in the semaglutide group and 15 (44.1%) in the standard therapy group (adjusted RR 1.18, 95% CI 1.02–1.36) in the no-IVT stratum (n = 68). The primary outcome was similar between two groups in the IVT-stratum. No severe adverse event was attributed to semaglutide treatment. This phase 2 trial suggested semaglutide was safe in patients with LVO and was associated with an improved neurological outcome in patients not receiving IVT. These preliminary observations should be confirmed in a phase 3 randomized trial (ClinicalTrials.gov Identifier: NCT05920889).