Background: This research work investigated the antidiabetic, anti-hyperlipidemic, and antioxidative effects of Anacardium occidentale methanolic nut extract in Streptozotocin (STZ)-induced diabetic Wistar rats. Methods: Forty (40) Wistar rats weighing 250±30g were randomly divided into five groups of 8 rats each. Group 1 served as the control; Group 2-5 were induced with diabetes with a single dose of 50mg/kg bw of streptozotocin intraperitoneally. After diabetes induction, Group 2 served as the STZ-only group, Groups 3 and 4 were administered 100mg/kg bw and 200mg/kg bw p.o Anacardium occidentale nut extract, respectively, while Group 5 was administered 2mg/kg bw of glimepiride as a reference drug for a period of 4 weeks. Food and water intake were monitored daily, body weight, and blood glucose levels weekly throughout the experiment. On day 29, the animals were sacrificed, and blood samples were collected through cardiac puncture for biochemical studies. Results: Administration of the nut extract significantly (p<0.05) increased the food intake and body weight of diabetic treated rats, fasting blood glucose level and oral glucose tolerance test (OGTT) decreased significantly (p<0.05) in treated rats. On lipid profile, administration of nut extract significantly decreased (p<0.05) triglyceride, low-density lipoprotein, total cholesterol, and very-low-density lipoprotein concentrations while it significantly increases (p<0.05) the high-density lipoprotein. Anacardium occidentale nut extract caused significantly (p<0.05) increases in SOD, GPx, GSH, and CAT levels with a decrease MDA level in diabetic treated rats. Markers of liver and kidney functions were also improved in diabetic treated rats.Conclusion: Treatment with Anacardium occidentale methanolic nut extract has hypoglycemic, hypolipidemic, and hepato-protective effects in diabetic rats. It also alleviates oxidative stress activity and restoration of markers of kidney function, and may be useful as alternative therapy in the management of diabetes and its related complications.