Pulmonary arterial hypertension (PAH) is a rare disease with poor prognosis and no therapeutics. PAH is characterized by severe remodeling of precapillary pulmonary arteries, leading to increased vascular resistance, pulmonary hypertension compensatory right ventricular hypertrophy, then heart failure and death. PAH pathogenesis shares similarities with carcinogenesis such as excessive cell proliferation, apoptosis resistance, metabolic shifts, or phenotypic transition. Although PAH is not a cancer, comparison of analogous mechanisms between PAH and cancer led to the concept of a cancer-like disease to emerge. MicroRNAs (miRNAs) are small noncoding RNAs involved in the regulation of posttranscriptional gene expression. miRNA dysregulations have been reported as promoter of the development of various diseases including cancers. Recent studies revealed that miRNA dysregulations also occur in PAH pathogenesis. In PAH, different miRNAs have been implicated to be the main features of PAH pathophysiology (in pulmonary inflammation, vascular remodeling, angiogenesis, and right heart hypertrophy). The review summarizes the implication of miRNA dysregulation in PAH development and discusses the similarities and differences with those observed in cancers.