(1) Introduction. Although pulmonary arterial hypertension (PAH) usually affects young people with a low cardiovascular risk profile, progressive epidemiologic changes have been providing a codified phenotype of elderly subjects with PAH and increased risk predictors for left heart disease. We therefore conducted a systematic review to describe the current knowledge and characteristics of elderly individuals with PAH and further insights concerning their prognostic outcomes and therapeutic response. (2) Methods. A search was conducted in PubMed, Embase, and Cochrane Library for publications evaluating the epidemiology, diagnostic work-up, and treatment of PAH in elderly subjects. (3) Among the 74 publications initially retrieved, 16 full-text articles were selected for the present systematic review. Compared to their younger counterparts, elderly individuals with PAH showed greater clinical deterioration, reduced exercise capacity, and worse prognostic outcomes, as well as less response to PAH-targeted therapy and higher rates of PAH drug discontinuation. (4) Conclusions. Demographic changes over time contributed to define a peculiar PAH phenotype in elderly patients, with an increased burden of cardiovascular comorbidities and distinctive features compared to young patients. Further investigations are needed in order to better clarify the nosologic criteria, and management in this subset population.