INTRODUCTION: Little is known about the optimal simulation-based team training in obstetric emergencies. We aimed to review how simulation-based team training affects patient outcomes in obstetric emergencies. MATERIAL AND METHODS: Search Strategy: MEDLINE, Embase, Cochrane Library, and Cochrane Central Register of Controlled Trials were searched up to and including May 15, 2021. SELECTION CRITERIA: randomized controlled trials (RCTs) and cohort studies on obstetric teams in high-resource settings comparing the effect of simulation-based obstetric emergency team training with no training on the risk of Apgar scores less than 7 at 5 min, neonatal hypoxic ischemic encephalopathy, severe postpartum hemorrhage, blood transfusion of four or more units, and delay of emergency cesarean section by more than 30 min. DATA COLLECTION AND ANALYSIS: The included studies were assessed using PRISMA, EPCO, and GRADE. RESULTS: We found 21 studies, four RCTs and 17 cohort studies, evaluating patient outcomes after obstetric team training compared with no training. Annual obstetric emergency team training may reduce brachial plexus injury (six cohort studies: odds ratio [OR] 0.47, 95% CI 0.33-0.68; one RCT: OR 1.30, 95 CI% 0.39-4.33, low certainty evidence) and suggest a positive effect; but it was not significant on Apgar score below 7 at 5 min (three cohort studies: OR 0.77, 95% CI 0.51-1.19; two RCT: OR 0.87, 95% CI 0.72-1.05, moderate certainty evidence). The effect was unclear for hypoxic ischemic encephalopathy, umbilical prolapse, decision to birth interval in emergency cesarean section, and for severe postpartum hemorrhage. Studies with in situ multi-professional simulation-based training demonstrated the best effect. CONCLUSIONS: Emerging evidence suggests an effect of obstetric team training on obstetric outcomes, but conflicting results call for controlled trials targeted to identify the optimal methodology for effective team training.