The global rise in obesity and its associated metabolic complications underscores the urgent need for safe and effective interventions. This study investigated the anti-obesity efficacy of a probiotic mixture containing Bifidobacterium breve BR3 and Lactiplantibacillus plantarum LP3 in C57BL/6 mice with high-fat diet (HFD)-induced obesity. After obesity was established by feeding a 60% kcal HFD, the probiotic mixture was administered orally for 4 weeks. Compared with the control group, mice receiving the L. plantarum LP3 and B. breve BR3 mixture exhibited significant reductions in body weight and total fat mass, as assessed by Dual-energy X-ray Absorptiometry (DXA) and Echo Magnetic Resonance Imaging (EchoMRI). The probiotic treatment also lowered serum Aspartate Aminotransferase (AST), Alanine Aminotransferase (ALT), and glucose levels, and attenuated lipid accumulation in both hepatic and epididymal adipose tissues. Transcriptomic profiling revealed upregulation of lipolytic genes (Sirt1, Pparα) and downregulation of lipogenic genes (Srebp1c, Fas), suggesting that the probiotic mixture promotes lipid catabolism while suppressing lipid synthesis. Additionally, serum adipokine levels were favorably modulated, indicating improved metabolic homeostasis. Gut microbiota analysis demonstrated an increased relative abundance of beneficial genera, including Akkermansia and Bacteroides, highlighting a microbiome-mediated contribution to the observed metabolic benefits. Overall, our findings indicate that the combined administration of Lactiplantibacillus plantarum LP3 and Bifidobacterium breve BR3 exerts multi-faceted anti-obesity effects by enhancing lipolysis, regulating lipid metabolism, and restoring a healthy gut microbial balance. This probiotic mixture represents a promising therapeutic approach for managing obesity and related metabolic disorders.