Sexual dysfunction is one of the diabetic complications in males. The present study aimed to evaluate the antidiabetic effect of α-mangostin and its protective role in sexual dysfunction of streptozotocin (STZ) induced diabetic male rats. Male Wistar rats were divided as control, diabetic control, diabetic rats administered with 25, 50 mg/kg body weight (bw) of α-mangostin and 1 mg/kg bw of gliclazide. The α-mangostin was administered once daily for a period of 55 days. On day 55 animals were sacrificed, serum was analyzed for testosterone levels, and sperm was collected from the epididymis and sperm parameters analyzed. Testis and epididymis were examined for antioxidant enzymes like superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx) levels, lipidperoxidation products, and histopathological alterations. In diabetic rats, sperm count, motile sperms, viable sperms, and hypo-osmotic swelling tail coiled sperms were significantly decreased while sperm malformations increased when compared with normal rats. Serum testosterone levels and testicular 3β and 17 β-hydroxysteroid dehydrogenase levels were significantly decreased in diabetic rats. Significant reduction in testicular and epididymal SOD, catalase, GPx levels, and elevation in lipid peroxidation products were observed. However, α-mangostin treatment showed noteworthy recovery in all parameters towards the control levels. It may therefore be suggested that α-mangostin showed a protective effect against sexual dysfunction in STZ induced diabetic rats.