In this review, we have discussed pulmonary hypertension including definition, classification, pathophysiology, epidemiology, diagnosis and treatment of each class of PH as per latest available data and guidelines. Pulmonary hypertension is defined as an increase in mean pulmonary arterial pressure of ≥ 20 mmHg at rest. The clinical classification of pulmonary hypertension (as per world health organization) includes five different classes constructed on the basis of clinical causes of pulmonary hypertension. The main pathophysiology involved in the development of pulmonary hypertension of all types is prolonged pulmonary vasoconstriction caused by multiple factors which ultimately leads to pulmonary vascular remodelling (structural as well as functional). The primary treatment of pulmonary hypertension comprises of correction/control of underlying cause of pulmonary hypertension. The prevalence of pulmonary hypertension is increasing in developed as well as developing countries and thus its awareness is important for timely diagnosis and management of this chronic condition. The main aim of our review is to provide all the necessary information regarding pulmonary hypertension in one document. KEYWORDS Pulmonary Hypertension, Chronic Thromboembolism, Left Heart Disease, Lung Disease, Pulmonary Arterial Hypertension