Heart failure due to diastolic dysfunction and pulmonary hypertension are frequent comorbid conditions with significant morbidity and mortality. Identifying the presence and etiology of diastolic dysfunction in the setting of pulmonary hypertension remains challenging despite profound therapeutic and prognostic implications. Additionally, there is little guidance in identifying and parsing etiology of diastolic dysfunction in patients found to have pulmonary hypertension. This review discusses the complex interplay between left ventricular diastolic dysfunction and pulmonary hypertension. With an explicit focus on the use of echocardiography for determination of diastolic dysfunction and etiology of pulmonary hypertension, this review also provides a comprehensive review of the literature and provides a framework by which to assess diastolic dysfunction echocardiographically in the setting of pulmonary hypertension.