Aim: Azadirachta indica A. Juss commonly called ‘Indian Lilac’ or ‘Margosa’ is used in the South West region of Cameroon to treat malaria, typhoid, intestinal worms and diabetes, and as mosquito repellent. Diabetes, a major risk factor for the development of cardiovascular diseases, is associated with long term damage, dysfunction, and failure of various organs, especially the eyes, kidneys, nerves, heart, and blood vessels. This study was designed to determine the phytochemical constituents and to investigate the anti-diabetic property of Azadirachta indica A. Juss seed oil obtained from the Far North region of Cameroon in alloxan induced diabetic Wistar rats. Method: An in vivo experimental study was conducted in the laboratory for preclinical animal studies and pharmaco-toxicology research, of FMBS, UY1 Cameroon. A study population of 135 albino Wistar rats with average mass 100 ± 20g was used. The phytochemical screening of the seed oil used was done using the GC-MS technique. The antihyperglycemic property of the oil was evaluated after oral glucose hyperglycemia induction, using 2g/kg body mass of glucose. The anti-diabetic property of the oil was evaluated over a period of 28 days, and blood glucose concentration after diabetes induction using alloxan solution in citrate buffer. The oral acute toxicity profile of the oil was evaluated over a period of 14 days following oral single dose 3 mL/100g administration of neem oil. Results: Physico-chemical results showed that the oil was composed mainly of five fatty acides (oleic acid (30-55%) being the most abundant and linoleic acid (11-26%) least abundant) and nineteen biochemicals with the three most abundant being: nonacosane (20.6575%), hentriacontane (14.1515%) and 2-methylbenzaldehyde (11.8674%). The oil was antihyperglycemic and maximum effect observed at 1mL/100g body mass, and at t=20minutes, compared to 0.5 mL and 1.5 mL. Conclusion: This study showed that neem oil have a promising preventive diabetic properties. The oil also proved to be antidiabetic at the doses of 0.5 mL, 1 mL and 1.5 mL per 100g body mass, with maximum effect observed with neem oil at 1ml/100g. Acute toxicity results showed no lethality at the maximum standard toxicity range of 2000mg/kg body weight.