Group 2 pulmonary hypertension (PH) is defined as PH due to left heart disease (PH-LHD), is the most common PH subtype worldwide. It affects up to 1% of the population and more than half of these patients has heart failure. Hence it is very important to clinically distinguish different subtypes of Group 2 PH as there is significant difference in pathophysiology, etiology and treatment strategies. Some of these subtypes are associated with worse outcomes. It is very challenging to differentiate these patients from other cardiac diseases due to overlapping symptoms and physical exam findings. Performing timely imaging and invasive hemodynamic monitoring is the key to early diagnosis so that we can modify disease progression, improve mortality and quality of life. Management for group 2 PH is significantly different than other subtypes of PH. This chapter aims to provide comprehensive summary of Group 2 pulmonary hypertension and its subtypes, pathophysiology, diagnosis and management. It will also highlight the areas needing further research to improve our understanding of this complex disease and further reduce disease burden in our patient population.