Background Lambda-cyhalothrin is a type II pyrethroid insecticide that is used for pest control in agricultural, domestic, and industrial settings. Glutathione is an antioxidant that has been reported to confer protection on biological systems against the adverse impacts of insecticides. Objective The aim of the study was to evaluate the effects of glutathione on the serum lipid profile and oxidative stress parameters of rats exposed to lambda-cyhalothrin toxicity. Methods Thirty-five rats were assigned into 5 groups each. Distilled water was given to the first group, whereas the second group received soya oil (1 mL/kg). Lambda-cyhalothrin (25 mg/kg) was administered to the third group. The fourth group was given lambda-cyhalothrin (25 mg/kg) and glutathione (100 mg/kg) successively, whereas the fifth group received lambda-cyhalothrin (25 mg/kg) and glutathione (200 mg/kg) consecutively. The treatments were administered once daily by oral gavage for 21 days. The rats were sacrificed after the completion of the study. The serum lipid profile and oxidative stress parameters were assessed. Results A significant (P < 0.05) increase was observed in the total cholesterol concentration of the lambda-cyhalothrin group. The serum malondialdehyde level was elevated (P < 0.05) in the lambda-cyhalothrin group. The superoxide dismutase activity of the lambda-cyhalothrin+glutathione200 group was enhanced (P < 0.05). The results revealed that lambda-cyhalothrin perturbed the total cholesterol concentration of the rats, whereas glutathione (particularly at 200 mg/kg, indicating a dose–response effect) ameliorated the disruptive impacts of lambda-cyhalothrin. Conclusion The advantageous effects of glutathione may be ascribed to its antioxidant property.