Diabetes mellitus is a widespread persistent metabolic disorder necessitating appropriate management to prevent its complications. The utilization of natural products in dietary adjustments is increasingly popular for the regulation of hyperglycemia. Our research aimed to assess the impact of avocado cold-pressed oil (ACPO) on the pancreas, kidneys, and liver of STZ-induced diabetic rats. An analysis of the components and antioxidative capacity of avocado cold-pressed oil were conducted. Forty-two Male Wister rats were segregated into six groups for the study. G1 served as the normal control, G2 received oral administration of ACPO, G3 received oral administration of Metformin, G4 (considered the positive control) was subjected to intraperitoneal STZ injection (40 mg/kg), and G5 comprised diabetic rats treated with ACPO orally. The group identified as G6 is comprised of diabetic rats who were orally administered metformin. The ACPO composition exhibited 25.77% saturated fatty acids, with the remaining 72.82% consisting of unsaturated fatty acids, predominantly oleic and palmitic. The radical scavenging activity of ACPO was favorable, as evidenced by its antioxidant effects against DPPH and NO. Moreover, ACPO led to a required decrease in blood glucose levels, and improvement in liver and kidney function parameters, albeit with only numerical reductions in lipid profile parameters. Additionally, ACPO mitigated histopathological abnormalities in the pancreas, kidneys, and liver, enhanced insulin expression in islets of Langerhans, and attenuated oxidative stress by suppressing iNOS expression in these organs. To summarize, the polyphenolic compounds present in ACPO played a crucial role in managing hyperglycemia, enhancing liver and kidney function, ameliorating histopathological lesions, and mitigating oxidative stress associated with diabetes mellitus.