Patients with multivessel coronary artery disease often receive 12 months of dual antiplatelet therapy (DAPT) after stenting to reduce the risk of ischemic events. Whether extending DAPT beyond 12 months in event-free patients with multivessel disease provides a benefit is uncertain. We conducted an open-label, randomized trial at 97 centers in China. Patients 18 to 75 years of age with multivessel coronary artery disease who had no major ischemic or bleeding events while receiving DAPT for 12 months after implantation of a drug-eluting stent were randomly assigned in a 1:1 ratio to receive an additional 12 months of DAPT (clopidogrel plus aspirin) or aspirin monotherapy. The primary efficacy end point was a composite of death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke. The primary safety end point was clinically relevant or major bleeding (i.e., a bleeding event of Bleeding Academic Research Consortium [BARC] type ≥2; BARC types range from 0 to 5, with higher values indicating greater severity of bleeding). A total of 8250 patients were randomly assigned to receive extended DAPT (4125 patients) or aspirin monotherapy (4125 patients). The median follow-up was 34.3 months. A primary efficacy end-point event occurred in 222 patients in the DAPT group and in 266 patients in the aspirin-monotherapy group (36-month Kaplan-Meier cumulative incidence, 5.8% vs. 6.8%; hazard ratio, 0.82; 95% confidence interval [CI], 0.69 to 0.98; P = 0.03). Clinically relevant or major bleeding occurred in 51 patients in the DAPT group and in 57 patients in the aspirin-monotherapy group (36-month Kaplan-Meier cumulative incidence, 1.4% vs. 1.5%; hazard ratio, 0.89; 95% CI, 0.61 to 1.30; P = 0.54). Among patients with multivessel coronary artery disease who were in stable condition 12 months after implantation of a drug-eluting stent, extending DAPT with clopidogrel and aspirin for an additional 12 months led to a lower risk of death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke than continuing aspirin alone, without an increased risk of bleeding. (Funded by the National Natural Science Foundation of China and others; DAPT-MVD ClinicalTrials.gov number, NCT04624854.).