Diisononyl phthalate (DIDP) is commonly used as a plasticizer in industrial and consumer products, however, its toxicity remains unclear. This study investigated the possible involvement of oxidative stress in DIDP-induced liver and kidney toxicity. Liver function and kidney function, tissue lesions, oxidative stress biomarkers, inflammatory mediators and apoptosis factors were investigated in this study. The results showed that oral exposure to DIDP induced a marked increase in lever of alanine aminotransferase (ALT), aspartate aminotransferase (AST), urinary nitrogen (UREA) and creatinine (CREA), decrease in albumin (ALB) level, as well as causing hepatic and renal histopathological change. Investigation of the role of oxidative stress pathways showed that DBP exposure could lead to a significant increase in levels of reactive oxygen species (ROS), malondialdehyde (MDA), 8-hydroxy-2-deoxyguanosine (8-OHdG), interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) and nuclear factor-κB (NF-κB), while a decrease in glutathione (GSH) levels were observed. Administration of vitamin E to DIDP-treated mice restored these biochemical parameters to within normal levels, and resulted in less damage to livers and kidneys. Overall, these results suggest that the oxidative stress pathway is involved in DIDP-induced toxicity.