Autism spectrum disorders are complex behavioral disorders that can be caused by exposure to valproic acid (VPA) during pregnancy. A therapeutic role for exercise training has been reported in many neurological diseases and problems, including autism. We aimed to evaluate various intensities of endurance exercise training and investigate its effects on oxidative and antioxidant factors in the liver of young males in a rat model of autism. Female rats were divided into a treatment (autism) and a control group. The autism group received VPA intraperitoneally on day 12.5 of pregnancy and the control pregnant females received saline. On the 30th day post‑birth, a social interaction test was performed on the offspring to confirm autistic‑like behavior. Offspring were divided into three subgroups: no exercise, mild exercise training, and moderate exercise training. Then the oxidative index of malondialdehyde (MDA) and the antioxidant indices of superoxide dismutase (SOD), total antioxidant capacity (TAC), and catalase in liver tissue were examined. The results of this study showed that both indices of sociability and social novelty decreased in the autism group. MDA levels in the liver of the autistic group increased, and moderate exercise training was shown to reduce the levels. Catalase and SOD activity as well as TAC levels decreased in the autism group, and moderate‑intensity exercise training was shown to increase the values. Parameters of hepatic oxidative stress were altered in VPA‑induced autism, and moderate‑intensity endurance exercise training was demonstrated to have beneficial effects on hepatic oxidative stress factors by modul ating the antioxidant/oxidant ratio.