BACKGROUND Previous reports suggest that risk factors, management, and outcomes of acute heart failure (AHF) may differ by sex, but they rarely extended analysis to low-and middle-income countries.OBJECTIVES In this study, the authors sought to analyze sex differences in treatment and outcomes in patients hospitalized for AHF in 44 countries.METHODS The authors investigated differences between men and women in treatment and outcomes in 18,553 patients hospitalized for AHF in 44 countries in the REPORT-HF (Registry to Assess Medical Practice With Longitudinal Observation for the Treatment of Heart Failure) registry stratified by country income level, income disparity, and world region. The primary outcome was 1-year all-cause mortality.RESULTS Women (n = 7,181) were older than men (n = 11,372), were more likely to have heart failure with preserved left ventricular ejection fraction, had more comorbid conditions except for coronary artery disease, and had more severe signs and symptoms at admission. Coronary angiography, cardiac stress tests, and coronary revascularization were less frequently performed in women than in men. Women with AHF and reduced left ventricular ejection fraction were less likely to receive an implanted device, regardless of region or country income level. Women were more likely to receive treatments that could worsen HF than men (18% vs 13%; P < 0.0001). In countries with low-income disparity, women had better 1-year survival than men. This advantage was lost in countries with greater income disparity (P-interaction < 0.001).CONCLUSIONS Women were less likely to have diagnostic testing or receive guideline-directed care than men. A survival advantage for women was observed only in countries with low income disparity, suggesting that equity of HF care between sexes remains an unmet goal worldwide. (J Am Coll Cardiol HF 2023;11:1262-1271) (c) 2023 by the American College of Cardiology Foundation.