Background <p>Visceral adiposity index (VAI) is a simple surrogate marker of visceral fat dysfunction and metabolic risk. Its association with diabetic kidney disease (DKD) remains unclear. This study aimed to evaluate the relationship between VAI and DKD risk through a meta-analysis of observational studies.</p> Methods <p>A systematic search of PubMed, Embase, Web of Science, and Cochrane Library was conducted up to March 14, 2025. Observational studies assessing the association between VAI and DKD were included. Two reviewers independently conducted study selection, data extraction, and quality assessment. Pooled estimates were calculated using STATA 15, and heterogeneity was assessed with the I² statistic. Sensitivity analyses were performed to test the robustness of the results. To identify potential sources of heterogeneity, we conducted subgroup analyses by study design, geographic region, index type (VAI vs. Chinese visceral adiposity index, CVAI), and DKD definition (composite vs. albuminuria-only), followed by meta-regression using these covariates.</p> Results <p>Nine studies involving 30,721 participants met the inclusion criteria. After adjusting for confounders, VAI was significantly higher in patients with DKD compared to those with diabetes alone (mean difference [MD] = 0.48; 95% confidence intervals (CI): 0.29–0.67; <i>p</i> &lt; 0.001; I² = 96.2%). A dose-response analysis showed that each unit increase in VAI was associated with an 11% increase in DKD risk (odds ratio [OR] = 1.11; 95% CI: 1.03–1.19). Compared with the lowest VAI quartile (Q1), the odds of DKD were progressively higher in Q2 (OR = 1.17), Q3 (OR = 1.33), and Q4 (OR = 1.62). Meta-regression identified the DKD outcome definition (composite vs. albuminuria-only) as a potential source of heterogeneity (<i>p</i> = 0.047), while study design, region, and index type (VAI vs. CVAI) had no significant impact. Subgroup and sensitivity analyses produced consistent findings, indicating a robust positive association between VAI and DKD. However, given the inclusion of cross-sectional studies, causality cannot be established.</p> Conclusions <p>This meta-analysis demonstrates that higher VAI is associated with an increased risk of DKD in patients with diabetes. However, given the observational design of included studies, causality remains uncertain. Prospective cohort studies are warranted to confirm the predictive value of VAI for DKD.</p> Trial registration <p>The study received registration and approval from PROSPERO (registration number: CRD420251046770).</p> Graphical Abstract <p></p>