We analyzed the clinical and pathological features of renal cell carcinoma (RCC) patients treated with cabozantinib stratified by body mass index (BMI). We retrospectively collected data from 16 worldwide centers involved in the treatment of RCC. Overall survival (OS) and progression-free survival (PFS) were analyzed using Kaplan–Meier curves. Cox proportional models were used at univariate and multivariate analyses. We collected data from 224 patients with advanced RCC receiving cabozantinib as second- (113, 5%) or third-line (111, 5%) therapy. The median PFS was significantly higher in patients with BMI ≥ 25 (9.9 vs. 7.6 months, p < 0.001). The median OS was higher in the BMI ≥ 25 subgroup (30.7 vs. 11.0 months, p = 0.003). As third-line therapy, both median PFS (9.2 months vs. 3.9 months, p = 0.029) and OS (39.4 months vs. 11.5 months, p = 0.039) were longer in patients with BMI ≥ 25. BMI was a significant predictor for both PFS and OS at multivariate analysis. We showed that a BMI ≥ 25 correlates with longer survival in patients receiving cabozantinib. BMI can be easily assessed and should be included in current prognostic criteria for advanced RCC.