A meta-analysis evaluated the efficacy and safety of probiotic/synbiotic supplementation in osteoporosis based on ten randomized controlled trials with 732 patients. PubMed, Embase, Web of Science and Cochrane databases were searched for studies until October 2025. Supplementation significantly improved bone mineral density of the lumbar spine (SMD: 0.85; 95% CI: 0.01, 1.69; P = 0.049) and reduced parathyroid hormone (SMD: −1.21; 95% CI: −2.19, −0.23; P = 0.02). No significant effects were found on hip bone mineral density, osteocalcin, C-terminal telopeptide, alkaline phosphatase, or osteoprotegerin. The risk of adverse events was not increased (RR: 1.03; 95% CI: 0.86, 1.23; P = 0.78). No publication bias was detected according to Egger's test and funnel plots. The authors concluded that probiotic/synbiotic supplementation may be a safe adjunctive treatment for osteoporosis, but larger multicenter studies are needed to confirm.