Background/Aims: Bariatric intervention has been reported to be an effective way to improve metabolic dysfunction-associated steatotic liver disease (MASLD) in obese individuals. The current systemic review aimed to assess the changes in MRI-determined hepatic proton density fat fraction (MRI-PDFF) and nonalcoholic fatty liver disease activity score (NAS) after bariatric surgery or intragastric balloon/gastric banding in MASLD patients with obesity. Methods: We searched various databases including PubMed, OVID Medline, EMBASE, and Cochrane Library. Primary outcomes were the changes in intrahepatic fat on MRI-PDFF and histologic features of metabolic dysfunction-associated steatohepatitis (MASH). Results: Thirty studies with a total of 3,134 patients were selected for meta-analysis. Bariatric intervention significantly reduced BMI (ratio of means, 0.79) and showed 72% reduction of intrahepatic fat on MRI-PDFF at 6 months after bariatric intervention (ratio of means, 0.28). Eight studies revealed that NAS was reduced by 60% at 3–6 months compared to baseline, 40% at 12–24 months, and 50% at 36–60 months. Nineteen studies revealed that the proportion of patients with steatosis decreased by 44% at 3–6 months, 37% at 12–24 months, and 29% at 36–60 months; lobular inflammation by 36% at 12–24 months and 51% at 36–60 months; ballooning degeneration by 38% at 12–24 months; significant fibrosis (≥F2) by 18% at 12–24 months and by 17% at 36–60 months after intervention. Conclusions Bariatric intervention significantly improved MRI-PDFF and histologic features of MASH in patients with obesity. Bariatric intervention might be the effective alternative treatment option for patients with MASLD who do not respond to lifestyle modification or medical treatment.