This study was conducted to determine the effects of vitamin E on growth performance, biochemical parameters, and antioxidant capacity of pufferfish (Takifugu obscurus) exposed to ammonia stress. The experimental basal diets supplemented with vitamin E at the rates of 2.31 (control), 21.84, 40.23, 83.64, 158.93, and 311.64 mg kg-1 dry weight were fed to fish for 60 days. After the feeding trial, the fish were exposed to 100 mg L-1 ammonia-nitrogen for 48 h. The results shown that the vitamin E group significantly improved weight gain, specific growth rate, and the expression levels of growth hormone receptors and insulin-like growth factor. Fish fed with the vitamin E-supplemented diets could increase plasma alkaline phosphatase activities and decrease plasma glutamicoxalacetic transaminase and glutamic-pyruvic transaminase activities. The relative expression levels of heat shock proteins (40.23-311.64 mg kg-1 vitamin E diet group), manganese superoxide dismutase (83.64-158.93 mg kg-1 vitamin E diet group), catalase (40.23-311.64 mg kg-1 vitamin E diet group), and glutathione reductase (40.23-311.64 mg kg-1 vitamin E diet group) were upregulated. On the other hand, the decreased level of reactive oxygen species (ROS) was observed in the 83.64-311.64 mg kg-1 vitamin E additive group. These results showed that vitamin E might have a potentially useful role as an effective antioxidant to improve resistance in pufferfish.