Entomopathogenic nematodes (EPNs) especially, Steinernema scaptersici are considered as an eco-friendly and natural lethal insect parasite. The virulence of nematode efficacy depends on the searching capability of infective juveniles (IJs) for willing infected hosts using a multiple array of host-emitted odors and CO2.The novel study on insect oxidative stress parameters as an indicator of nematode toxicity towards Locusta migratoria 5th stage nymphs were evaluated in the present investigation. The effects of different doses (0 - 50 IJs/µL) of nematodes and post injection times (12, 24 h), on different tissues (brain, thoracic muscles, and gut) of 5th nymphal stage L. migratoria were examined. The obtained results revealed a significant fluctuation in the concentration of hydrogen peroxide (H2O2), total antioxidant ability (TAA), and reducing power ability (RPA). Also, a comparable significant fluctuation pattern of the antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD) activities was detected. Besides that, positive correlation was detected among different nematodes concentrations (0-50 IJS/µL) and H2O2, TAA, CAT, or SOD at 24 h post injection (PI) in brain and thoracic muscle tissues of treated insects. Significant elevations in the reactive oxygen species (ROS) concentration and antioxidant activities in all the treated tissues of L. migratoria 5th nymphs with different nematode concentrations (0-50 IJs/µL) were also detected. Besides that, the levels of H2O2 showed a significant increase in the gut than the brain and thoracic muscles tissues. However, the TAA concentration level was lower at 24 h than 12 h post injection. So, these results emphasized the hypothesis of after nematode infection, the activation of certain host protective mechanisms can occur including antioxidant and detoxification pathways. Therefore, the oxidative stress parameter changes of grasshopper tissues toward time-concentration dependent model of nematode infection may help in a further investigation of the nematode toxicity in field application.