Background CAR-T-cell therapy and bispecific antibody have revolutionized the treatment landscape for multiple myeloma. However, there is currently a lack of studies comparing the efficacy and safety of these two approaches. This meta-analysis assesses the efficacy and safety of B-cell maturation antigen (BCMA)-directed CAR-T-cell therapies and BCMAxCD3 bispecific antibodies as third-line or later interventions for relapsed/refractory multiple myeloma (RRMM). Methods We searched PubMed, Embase, Web of Science, and Cochrane databases up to May 31, 2024, identifying 11 eligible studies encompassing 1269 participants. Random-effects models evaluated the primary (complete response (CR) rate) and secondary (overall response rate (ORR)) outcomes, while meta-regression analyses adjusted for relevant covariates. Results CAR-T-cell therapy achieved significantly higher pooled CR rate (0.54 (95% CI 0.42-0.69) vs bispecific antibodies 0.35 (0.30-0.41), p<0.01) and pooled ORR (0.83 (0.76-0.90) vs 0.65 (0.59-0.71), p<0.01). However, CAR-T therapy had a higher incidence of adverse events, particularly cytokine release syndrome (CRS 0.83 (0.70-0.97) vs bispecific antibodies 0.59 (0.43-0.74), p<0.05). Severe CRS (grade >= 3) occurred at a rate of 0.07 (0.03-0.14) in the CAR-T cell group, contrasting with a negligible rate of 0.01 (0.00-0.02) in the bispecific antibody group (p<0.01). Hematologic adverse events, including neutropenia (grade >= 3; 0.88 (0.81-0.95) vs 0.48 (0.30-0.67), p<0.01) and anemia (grade >= 3; 0.55 (0.47-0.62) vs 0.34 (0.28 to 0.40), p<0.01), were also more frequent in the CAR-T-cell group. Furthermore, differences in efficacy were observed among various CAR-T products, with ciltacabtagene autoleucel showing greater efficacy in CR rate (0.77 (0.71-0.84) vs 0.37 (0.32-0.41), p<0.01) and ORR (0.91 (0.83-0.99) vs 0.73 (0.68-0.77), p<0.01) compared with idecabtagene vicleucel. Conclusion CAR-T-cell therapy demonstrated superior CR rates compared with bispecific antibodies, although with an increase in severe adverse events.