Alangium salvifolium is a plant that is traditionally used to treat many diseases like laxative, antiepileptic, jaundice, antiulcer agent, agent to alleviate spasms, anthelmintic, emetic, antiprotozoal agent and hypoglycemic agent. Its subspecies Alangium salvifolium subsp. Hexapetalum (Wangerin) is also known for a variety of traditional use like hemorrhoids, rheumatism, and antidote for snake bite. The present work aims for the evaluation of the in-vitro and in-vivo anti-diabetic activity of methanolic extract of aerial parts of Alangium salvifolium subsp. Hexapetalum (Wangerin). The in-vitro antidiabetic activity was evaluated by a starch-iodine color assay method. The in-vivo method was performed by administering orally the methanolic extract of Alanghium salvifolium subsp. Hexapetalum in streptozotocin-induced male Albino Wistar rats weighing 200 g. The study was compared using standard metformin hydrochloride (10 mg/kg body weight). The in-vitro method showed a dose-dependent anti-diabetic activity that is as the dose increases the percentage inhibition of enzyme activity also increases. The in-vivo anti-diabetic activity was accessed by comparing the body weight and blood glucose level on 0th, 5th, 10th and 15th day using a glucometer. Thus, the present study reveals that the methanolic extract of aerial parts of Alanghium salvifolium subsp. Hexapetalum (Wangerin) was efficient in lowering blood glucose levels.