Background Pulmonary arterial hypertension (PAH) is a devastating illness of pulmonary vascular remodeling, right-sided heart failure, and limited survival. Whether strain-based measures of right ventricular (RV) systolic function predict future right-sided heart failure and/or death is untested. Methods RV longitudinal systolic strain and strain rate were evaluated by echocardiography in 80 patients with World Health Organization group 1 pulmonary hypertension (PH) (72% were functional class FC III or IV). Survival status was assessed over 4 years. Results All patients had a depressed RV systolic strain (−15% ± 5%) and strain rate (−0.80 ± 0.29 s−1 ). Of the parameters assessed, average RV free wall systolic strain worse than −12.5% identified a cohort with greater severity of disease (82% were FC III/IV), greater RV systolic dysfunction (RV stroke volume index 26 ± 9 mL/m2 ), and higher right atrial pressure (12 ± 5 mm Hg). Patients with an RV free wall strain worse than −12.5% were associated with a greater degree of disease progression within 6 months, a greater requirement for loop diuretics, and/or a greater degree of lower extremity edema, and it also predicted 1-, 2-, 3-, and 4-year mortality (unadjusted 1-year hazard ratio, 6.2; 2.1–22.3). After adjusting for age, sex, PH cause, and FC, patients had a 2.9-fold higher rate of death per 5% absolute decline in RV free wall strain at 1 year. Conclusions Noninvasive assessment of RV longitudinal systolic strain and strain rate independently predicts future right-sided heart failure, clinical deterioration, and mortality in patients with PAH.