The left atrium (LA) plays an important role in facilitating left ventricular (LV) filling by acting as a reservoir, passive conduit, and active booster pump, as well as a regulator of blood volume through A-type natriuretic peptide secretion in response to stimulation by mechanical stretch of the cavity. LA myopathy has emerged as one of the most important non-LV contributors to disease progression in heart failure with preserved ejection fraction (HFpEF). LA dysfunction is common in HFpEF and is associated with more severe pulmonary vascular disease and right ventricular dysfunction, and increases the risk of incident atrial fibrillation or atrial functional mitral regurgitation, leading to limitations in cardiac output reserve and reduced exercise capacity. LA deformation assessed by 2-dimensional speckle-tracking echocardiography is useful for estimating abnormal hemodynamics or exercise capacity, discriminating HFpEF from non-cardiac dyspnea and is an independent predictor of adverse outcome in HFpEF. Thus, interventions directly targeting LA myopathy may improve outcomes in HFpEF with LA myopathy. This review provides information regarding the physiology of the LA in patients with HFpEF and discusses the importance of evaluation of LA function, management issues, and future directions through ongoing trials of medical interventions.