This meta-analysis aimed at exploring the impact of opioid-free anesthesia (OFA) on pain score and opioid consumption in patients undergoing bariatric surgery (BS). Literature search identified eight eligible trials. Forest plot revealed a significantly lower pain score (mean difference (MD) =  − 0.96, p = 0.0002; 318 patients), but not morphine consumption (MD =  − 5.85 mg, p = 0.1; 318 patients) at postoperative 24 h in patients with OFA than in those without. Pooled analysis also showed a lower pain score (p = 0.002), morphine consumption (p = 0.0003) in the postanesthetic care unit, and risk of postoperative nausea/vomiting (p = 0.0003) in the OFA group compared to the controls. In conclusion, this meta-analysis demonstrated that opioid-free anesthesia improved pain outcomes immediately and at 24 h after surgery without a beneficial impact on opioid consumption at postoperative 24 h.

• Roles of opioid-free anesthesia (OFA) in bariatric surgery (BS) were investigated.

• Outcomes included postoperative pain score, opioid use, and nausea/vomiting risk.

• OFA was associated with lower 24-h pain score but not opioid consumption.

• Lower pain score and opioid consumption were noted in the postanesthetic care unit.

• OFA correlated with a lower risk of postoperative nausea/vomiting.