Abstract Aims Sodium-glucose cotransporter 2 (SGLT-2) inhibitors have now been evaluated for the treatment of heart failure in several placebo-controlled randomized controlled trials (RCTs) across various ejection fraction ranges, but these trials were powered for composite outcomes rather than individual clinical endpoints. We therefore performed a meta-analysis to assess their safety and efficacy on all-cause mortality, cardiovascular mortality, and heart failure hospitalizations. Methods and results We performed a prospectively registered random-effects meta-analysis of all RCTs comparing SGLT-2 inhibitors to placebo in patients with heart failure. The pre-specified primary endpoint was all-cause mortality. Secondary endpoints included cardiovascular mortality, heart failure hospitalizations, and the composite of cardiovascular mortality or heart failure hospitalization. Four trials with 15 684 patients were eligible. The SGLT-2 inhibitor tested was empagliflozin in two trials, dapagliflozin in one trial, and sotagliflozin in one trial. The weighted-mean follow-up was 20.0 months. The hazard ratio (HR) for all-cause mortality was 0.91, 95% confidence interval (CI) 0.82–1.01, P = 0.071. There was a 12% reduction in cardiovascular mortality (HR 0.88, 95% CI 0.79 to 0.97, P = 0.012), and a 30% reduction in heart failure hospitalization (HR 0.70, 95% CI 0.64 to 0.77, P < 0.001). Conclusion SGLT-2 inhibitors significantly reduced cardiovascular mortality and heart failure hospitalizations in patients with heart failure. The effect appears consistent across three drugs studied in four trials. SGLT-2 inhibitors should become standard care for patients with heart failure.