This study aims to determine the reliability of the Beck Depression Inventory (BDI), a widely used tool for diagnosing depression--a condition that significantly impacts individuals' lives--through meta-analysis, an advanced statistical technique. To achieve this objective, studies conducted in Turkey between 1961 and 2021 that utilized the Beck Depression Inventory were included. Relevant studies were identified through searches in the "Higher Education Council (HEC) National Thesis Center" and Google Scholar databases. The inclusion criteria focused on studies that reported validity and reliability analyses and contained the keywords "Beck Depression Inventory" or "Beck Depression Scale." The effect size was calculated using the Cohen's d formula. The meta-analysis revealed an overall reliability coefficient of 0.88 for the Beck Depression Inventory, which, based on Cohen's d classification, represents a large effect size.