Previously considered a disease isolated to the pulmonary circulation, pulmonary arterial hypertension is now being recognized as a systemic disorder that is associated with significant metabolic dysfunction. Numerous animal models have demonstrated the development of pulmonary arterial hypertension following the onset of insulin resistance, indicating that insulin resistance may be causal. Recent publications highlighting alterations in aerobic glycolysis, fatty acid oxidation, and the tricarboxylic acid cycle in the pulmonary circulation and right ventricle have expanded our understanding of the complex pathobiology of this disease. By targeting these derangements in metabolism, numerous researchers are investigating noninvasive techniques to monitor disease activity and therapeutics that address the underlying metabolic condition. In the following review, we will explore pre-clinical and clinical studies investigating the metabolic dysfunction seen in pulmonary arterial hypertension.