Pulmonary arterial hypertension (PAH) is an important cause of morbidity and mortality in children. Improved understanding of the pathophysiological mechanisms of the underlying diseases has resulted in the development of effective, but not yet curative, therapies. Currently, drugs from three main pharmacological groups targeting specific aberrant pathways (endothelin, nitric oxide, and prostacyclin) and four routes of administration (inhaled, intravenous, oral, and subcutaneous) have been approved for adult patients with PAH. However, only a minority of these drugs has been officially approved for children, mainly because randomized controlled studies are limited by the small number of paediatric patients with PAH worldwide. In children with progressive, severe PAH and an inadequate response to drug therapy, advances in interventional and surgical approaches have provided promising new strategies to avoid right ventricular deterioration. These techniques can delay or even avoid the need for lung transplantation. In this Review, we present an update on developments in drug therapy for patients with PAH and highlight the current status of these treatments in children. We also describe the new surgical, interventional, and hybrid procedures, as well as their practical application in children with severe PAH.