<p>Probiotic supplementation has been proposed as an adjunct strategy to optimize metabolic recovery following surgery. This systematic review and meta-analysis aimed to evaluate the effects of probiotics on metabolic outcomes in patients undergoing bariatric surgery. A comprehensive literature search was conducted in PubMed, Embase, Scopus, and the Cochrane Library. Randomized controlled trials assessing probiotic supplementation on glycemic indices, lipid profiles, and anthropometric outcomes after bariatric surgery were included. Given anticipated heterogeneity, a random-effects model was used, and outcomes with extreme heterogeneity (I² ≥ 75%) were supplemented with narrative synthesis.&#xa0;Pooled effect sizes were calculated using a random-effects model. Thirteen randomized controlled trials were synthesized. Probiotic supplementation significantly reduced fasting blood glucose (WMD = − 5.66 mg/dl; 95% CI: − 9.15 to − 2.17; <i>p</i> = 0.001; I² = 0.0%). In contrast, there was no significant overall effect on HbA1c (<i>p</i> = 0.991), fasting insulin (<i>p</i> = 0.265), or HOMA-IR (<i>p</i> = 0.73). Furthermore, no significant effects were observed across the entire lipid profile (<i>p</i> &gt; 0.05). Overall BMI (<i>p</i> = 0.763) and %EWL (<i>p</i> = 0.645) were unaffected, although strain-specific subgroup analysis for BMI suggested differential effects between <i>Lactobacillus</i>/<i>Bifidobacterium</i> combinations. Due to extreme heterogeneity, the trend toward improved vitamin B12 levels (<i>p</i> = 0.058; I² = 96.2%) was deemed unreliable and confounded by routine postoperative vitamin use. Probiotic supplementation significantly improves fasting blood glucose levels in patients following RYGB or SG. However,&#xa0;the evidence is limited by short follow-up and high heterogeneity.&#xa0;There is no consistent evidence supporting its use for improving HbA1c, lipid profiles, or overall anthropometric measures in this population.</p>