Previous studies have shown high triglyceride (TG) is associated with platelet hyperactivation in metabolic syndrome patients. However, limited information is available regarding this relationship on dual anti-platelet therapy (DAPT) in ischemic stroke (IS). In this study, we attempted to evaluate the association between TG and high on-treatment platelet reactivity (HTPR) in IS patients.Ischemic stroke patients who received maintenance doses of clopidogrel and aspirin were categorized and analyzed retrospectively in this research. The platelet reactivity was assessed by Thromboelastography (TEG). If ADP-induced platelet inhibition rate (ADPi)<30%, it was defined as HTPR, else, it would be defined as normal on-treatment platelet reactivity (NTPR). Patients were divided into high-TG-level and lower-TG-level based on a TG level of 1.7mmol/L, the cutoff point of hypertriglyceridemia. A logistic regression model was applied to calculate the odds ratio (OR) and 95% confidence interval (CI).A total of 123 patients were included in this study and 24 (19.51%) patients were identified as HTPR. HTPR was observed in 36.2% of the patients in high-TG-level (TG≥1.7mmol/L) group while only 9.2% of the patients in the low-TG-level group (TG<1.7mmol/L) were HTPR (P<0.001 ). According to multivariate analysis, TG≥1.7mmol/L was independently associated with HTPR (OR=14.715, 2.445-88.549,P=0.003).High TG is an independent predictor of HTPR in IS patients. For IS patients with high TG level undergoing DAPT, platelet reactivity should be monitored to identify HTPR, which may proactively help to optimize the anti-platelet therapy.Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.