<p>Heart failure (HF) is not confined to contractile failure of cardiomyocytes or myocardial fibrosis. Coronary and systemic vascular dysfunction contributes to the initiation and progression of HF with or without reduced ejection fraction. Furthermore, HF compromises vascular function, creating and sustaining a vicious cycle with deranging effects on coronary blood flow, cardiac metabolism and cardiac function. In HF, systemic arterial dysfunction, characterized by increased arterial stiffness and resistance, raises cardiac afterload and impedes myocardial contractile function. Reduced coronary blood flow impairs myocardial oxygen delivery and consequently cardiomyocyte metabolism and function. Coronary microvascular dysfunction is heterogeneous in its pathogenesis and manifestations, complicating the diagnosis and management across different HF phenotypes. Understanding the alterations in function in different segments of the vasculature, from the aorta to the capillary level, offers mechanistic insights into disease drivers and therapeutic interventions. Interventional approaches can improve vascular haemodynamics, whereas established and emerging pharmacotherapies target the neurohumoral axis and reduce extravascular compression, inflammation, and oxidative stress, thereby improving vascular function and HF-related outcomes. In this Review, we provide a mechanistic framework of vascular dysfunction in the pathogenesis of HF with or without reduced ejection fraction, pointing towards integrated therapies that consider the vascular implications of contemporary HF management across HF phenotypes.</p>