Background <p>Type 2 diabetes mellitus (T2DM) is a global health concern characterized by insulin resistance and impaired insulin secretion. Traditional markers have limitations in early detection. Adipsin, an adipokine involved in insulin secretion and β-cell function, may serve as a novel biomarker for T2DM diagnosis.</p> Objective <p>This meta-analysis evaluates serum adipsin levels in individuals with T2DM to assess its potential as a biomarker.</p> Methods <p>A systematic search was conducted in PubMed, including observational studies, cohort, and cross-sectional studies. Data extraction was done independently by two reviewers, and pooled analysis was performed using a random-effects model. Mean differences in serum adipsin levels between T2DM patients and controls were calculated.</p> Results <p>Eight studies were included in our study. The pooled mean serum adipsin level in T2DM patients was 3.44&#xa0;ng/mL (95% CI 2.72–4.15), significantly lower than in controls 6.01&#xa0;ng/mL (95% CI 4.26–7.75, <i>p</i> = 0.01) with mean difference − 2.47&#xa0;ng/mL (95% CI − 4.49 to − 0.45). Heterogeneity was high across studies (<i>I</i>² = 85.61% for T2DM, <i>I</i>² = 94.3% for controls).</p> Conclusion <p>The results show significantly lower serum adipsin levels in T2DM patients, supporting its promising, biomarker. Reduced adipsin levels may contribute to T2DM pathophysiology by affecting insulin regulation and glucose metabolism. Serum adipsin is a promising biomarker for T2DM diagnosis. Further research is needed to explore its clinical utility and therapeutic potential in managing T2DM.</p>