Diabetes mellitus is a metabolic condition wherein the body's blood sugar levels are elevated. Plant-based treatments are less toxic than allopathic pharmaceuticals. Plumeria alba Linn (Apocynaceae) is a popular medicinal plant that contains flavonoids, tannins, alkaloids, terpenoids, and antioxidants. The antihyperglycemic action of Plumeria alba Linn. leaves, on the other hand, has yet to be determined. A Streptozotocin-nicotinamide-induced Type II diabetes model was used to elaborate on the hypoglycemic activity of ethanolic and aqueous leaf extractives of Plumeria alba, which were compared to the diabetic control group. Anti-diabetic activity was tested on albino Wistar rats. Normal and experimental rats were given ethanolic and aqueous leaf extracts at 250 mg/kg b.w. and 500 mg/kg b.w. for 21 days, and the effect on blood sugar levels was measured. In comparison to the diabetic control group, the ethanolic extract at a dose of 500 mg/kg b.w. exhibits a highly significant (p<0.001) reduction in blood glucose levels.