The present study was aimed to evaluate the antihyperglycemic and antioxidant effects of Nepeta hindostana (NH) whole herb extract in alloxan and OGTT induced diabetes in rats. In this study, aqueous (NHA) and methanolic (NHM) extract of NH were prepared and qualitative and quantitative phytochemical screening was done to identify the different chemical constituents present in the extracts. Isolation of chemical constituents was carried via column chromatography using chloroform and ethyl acetate (10:4). In-vitro antioxidant potential of NHA and NHM extract was evaluated by employing DPHH, hydroxyl, superoxide radical and nitric oxide scavenging activity whereas invivo anti-oxidant activity was evaluated by measuring the reduced glutathione and catalase level. The antidiabetic activity was evaluated employing OGTT and alloxan (150 mg/kg, i.p.) induced diabetes in rats. The rats were divided into control, diabetic control and treatment group and different doses (100, 200 and 400 mg/kg) of NHA and NHM extract were administered. Various biochemical parameters i.e blood glucose, total cholesterol, triglyceride, LDL, VLDL and HDL level were estimated. In NHM extract, total flavonoids and total terpenoids were found to be present in major amount. The isolated compound (I) was identified as triterpenoidal aldehyde of lupine series. NHA and NHM extract significantly attenuated in-vitro and in-vivo oxidative stress. Moreover, hyperglycemia induced by OGTT and alloxan was also found to be significantly attenuated by different doses of NHA and NHM.