Whole-body vibration training (WBVT) is considered a time-saving, low-impact exercise modality that may aid in body mass management. However, the effectiveness of WBVT in changing body composition remains unclear. This systematic review and meta-analysis evaluated the effects of WBVT on body mass, body mass index (BMI), and fat mass across different BMI and age categories. A systematic search of PubMed, Cochrane Library, Web of Science, Embase, Scopus, and SPORTDiscus was performed to identify randomized controlled trials (RCTs) investigating the effects of WBVT on weight-related outcomes. Studies published up to December 25, 2024 were screened according to PRISMA guidelines, and risk of bias was assessed using the Cochrane tool. Meta-analyses were performed using mean differences (MDs) and 95% confidence intervals (CIs) under fixed or random-effects models. Twenty RCTs with 585 participants were included. WBVT alone had no significant effect on body mass (MD = 0.04), BMI (MD = -0.24), fat mass (MD = -0.90), fat-free mass (MD = 0.15), or body fat percentage (MD = 0.04%). Subgroup analysis by BMI showed no significant differences across weight categories. However, age-based subgroup analysis revealed that participants aged ≥50 years experienced a greater reduction in body fat percentage (MD = -1.79%) than those <50 years (MD = 0.46%; p = 0.008), suggesting a potential age-related effect. Overall risk of bias was rated as low to moderate. WBVT alone did not significantly reduce body mass or fat mass, but it remains a promising intervention due to its neuromuscular and metabolic benefits. Future studies should explore optimized WBVT parameters, potential metabolic adaptations, and synergies with other interventions to enhance its applicability in body mass management.