This review provides an overview of recent advances in the pathobiology, classification, and treatment strategies of paediatric pulmonary hypertension (PH). Current registries have begun to provide differences in aetiology and clinical course between adult and paediatric forms of PH. For example, in the majority of patients, PH in children is idiopathic or associated with congenital heart disease (CHD); PH associated with connective tissue disease (CTD) is rare in children. Recent studies of paediatric PH have highlighted unique aspects of the pathogenesis and challenging treatments in idiopathic pulmonary arterial hypertension (IPAH) or associated pulmonary arterial hypertension. Although treatment with new selective pulmonary vasodilators offers haemodynamic and functional improvement in paediatric populations, treatments in children still depend on results from larger adult studies and experience of clinicians treating children. Future studies are required for development of specific strategies for children with PH.