MicroRNAs have emerged as key players of gene regulation during development and disease states like cancer and cardiovascular diseases. Pulmonary arterial hypertension (PAH), a vascular disease characterized by pulmonary resistance and vessel occlusion, is not spared by microRNA implication. This is not surprising since PAH shares common aberrantly activated pathways with cancers that lead to proliferation and survival of pulmonary arterial smooth muscle cells, among others, within the artery wall and narrowing the lumen. Recent studies demonstrated the role of miR-204 and miR- 206 in pulmonary artery smooth muscle cell (PASMC) proliferation. Other microRNAs, such as miR-145, miR-21 and the miR17/92 cluster, have been associated with the disrupted BMPR2 pathway. During the last couple of years, the number of studies on the role of microRNA in PAH has broadened, defining it clearly as a HOT TOPIC. This current review presents an overview of the most recent knowledge as well as future possibilities. The use of microRNA therapies is still uncertain and poorly applied in the clinical setting yet. It is still critical to increase the knowledge and the translational potential of this HOT TOPIC to make it become a HOPE TOPIC.