Pulmonary arterial hypertension (PAH) may complicate diverse connective tissue diseases (CTDs) such as systemic sclerosis (SSc), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and mixed CTD (MCTD) and is an important cause of morbidity and mortality in this context. From a histological standpoint, the pulmonary vascular lesions in PAH complicating CTD are similar to those observed in idiopathic PAH (IPAH). However, prognosis and responsiveness to therapy are distinctly worse in PAH associated with CTD. PAH is most common in SSc (affecting up to 20% of patients with SSc), and most of the data regarding incidence, clinical features, and therapy of CTD-associated PAH are derived from patients with SSc (scleroderma). Although PAH may involve other CTDs, data are more limited (primarily small, uncontrolled series and case reports). Treatment strategies for PAH associated with CTD are similar to but are distinctly less effective than those for IPAH. Lung transplantation may be offered for a subset of patients with CTD-associated PAH, but results are less favorable than for IPAH due to comorbidities and specific complications associated with CTD (e.g., esophageal involvement, aspiration with SSc).