Background and Purpose: Prunus amygdalus (PA) is a popular invasive seed utilized in the management of diabetes in Jammu and Kashmir, India. The current study scrutinizes the antihyperglycemic effect of PA on Streptozotocin (STZ) induced diabetic rats. Experimental approach: BBD was performed to determine the effect of PA powder on methanol, extraction time and extraction temperature on DPPH and ABTS free radical scavenging activity of decoction. Oral glucose tolerance test (OGTT) executed for the estimation of glucose utilization by PA extract. Type II diabetes mellitus was initiated by single intraperitoneal injection of STZ. The Blood Glucose Level (BGL) and body weight were estimated at regular interval of time. Different biochemical parameters; hepatic parameters; antioxidant parameters and lipid parameters were estimated followed by histopathological observation. of pancreas Key Results: The variation observed were DPPH antiradical scavenging activity 40.0-90.0% and ABTS antiradical scavenging activity 34-82%, respectively. OGTT study, PA treatment significantly (P<0.001) down-regulated the BGL level 170, 142.66 and 100.36 mg/dL at 50, 100 and 200 mg/kg, respectively. PA significantly (P<0.001) altered the biochemical, hepatic and antioxidant parameters in a dose-dependent manner. Further alteration of antioxidant parameters, hepatic and renal parameters were also observed. Histopathological examination demonstrated the increased mass of β-cells in the pancreas. Conclusions & Implications: Consequently, we can say that response surface methodologies successfully carry out the extraction of Prunus amygdalus with the highest antioxidant effect and PA treatment would be helpful in the preclusion of diabetes and its complications.