<p>Atherogenic index of plasma (AIP) has emerged as a novel marker of atherosclerosis and a predictor of outcomes in patients with coronary artery disease. However, the prognostic significance of AIP in a distinct population with myocardial infarction with nonobstructive coronary arteries (MINOCA) remains unclear. This prospective cohort study included 1179 patients with MINOCA who were stratified by the tertile levels of AIP defined as base 10 logarithm of the ratio of fasting triglyceride to high-density lipoprotein cholesterol. The primary endpoint was major adverse cardiovascular events (MACE) including all-cause death, reinfarction, stroke, revascularization and hospitalization for unstable angina or heart failure. Over the median follow-up of 41.7 months, patients with higher AIP tertiles had more cardiometabolic risk factors and a significantly higher incidence of MACE (9.9%, 14.3%, 18.6%; <i>p</i> = 0.002). Elevated AIP was associated with an increased risk of MACE even after multivariable adjustment [tertile 1 of AIP as reference; tertile 2: hazard ratio (HR) 1.50, 95% confidence interval (CI): 1.03–2.32, <i>p</i> = 0.036; tertile 3: HR 1.78, 95% CI: 1.21–2.63, <i>p</i> = 0.003]. AIP as a continuous marker remained a robust risk factor in all patients and across subgroup analyses. A near-linear relationship was observed between AIP levels and the risk of MACE following MINOCA. Moreover, AIP showed a moderate ability to predict MACE with an area under the curve of 0.67. Higher AIP levels were independently associated with poorer outcomes after MINOCA. These data indicate the role of atherogenic dyslipidemia in MINOCA pathogenesis and support the utility of AIP for risk stratification in this population.</p>