Diabetes mellitus is a disease characterized by an increase in blood glucose levels or hyperglycemia. It is the third most deadly disease in the world, and Indonesia ranks as the fourth-highest country in terms of diabetes prevalence. One potential natural ingredient for controlling blood glucose levels is peanut shell extract, as it contains flavonoid compounds that can help lower blood glucose levels. This study aims to evaluate the antidiabetic activity of ethanol extract from peanut shells in glucose-induced white rats. The research was conducted as an experimental study by extracting peanut shells using the maceration method with 96% ethanol as the solvent. A completely randomized design (CRD) was used, consisting of six treatment groups: normal control rats, positive control (glibenclamide), negative control (distilled water), and three treatment groups with extract doses of 100 mg/kgBW, 200 mg/kgBW, and 400 mg/kgBW. The peanut shell extract was administered orally (via gavage) for 35 days. Blood glucose levels in rats were measured before and after treatment. Data analysis was conducted using a paired t test with SPSS 16.0 at a 95% significance level. The results showed that the ethanol extract of peanut shells contains flavonoid compounds capable of reducing blood glucose levels. This indicates that the ethanol extract of peanut shells exhibits antidiabetic effects in glucose-induced white rats, with the highest reduction observed at a dose of 400 mg/kgBW (p = 0.000).