The study compared proportional assist ventilation plus (PAV+) with pressure support ventilation (PSV) in critically ill adult patients during weaning from mechanical ventilation. PAV+ provides assistance proportional to the patient's inspiratory effort, improving synchronization with the ventilator and reducing the work of breathing. Seven randomized controlled trials with 1214 patients were analyzed. The primary outcome was weaning success rate, with PAV+ achieving a better outcome (RR = 1.12, 95% CI: 1.02–1.23). This effect remained significant in sensitivity analyses, except for the spontaneous breathing studies. No differences were found in reintubation, ICU and in-hospital mortality, ICU length of stay, or weaning duration. The study is registered in PROSPERO (CRD420251170692).