A trial was conducted to investigate whether, and if so to what extent, the combined supplementation of vitamin E, vitamin C, and selenium was superior to their sole supplementation concerning the oxidative stress induced by a high n-3 dietary polyunsaturated fatty acids (PUFA) intake in broilers. Four hundred 21-day-old Ross 308 male broilers were allocated to 5 experimental groups fed the following linseed oil (5%)-enriched finisher diets: Cont (no supplement), +E (200 IU vitamin E/kg feed), +C (250 mg vitamin C/kg feed), +Se (0.2 mg selenium/kg feed), or +ECSe (concentrations as in the sole supplementation, combined). Analyses of malondialdehyde (MDA), vitamin C, and α- and γ-tocopherols in plasma, antioxidant capacity of water- (ACW) and lipid- (ACL) soluble compounds in serum, and glutathione peroxidase (GPx) and superoxide dismutase (SOD) activities in whole blood were performed. In breast muscle, analyses of MDA, α- and γ-tocopherols, ACW, selenium, and fatty acid (FA) composition were carried out. Birds fed the combination of antioxidants showed reduced average daily gain (ADG) and average daily feed intake (ADFI) and, as +E, lower MDA and γ-tocopherol, together with raised α- tocopherol levels in plasma and lower MDA and raised α- tocopherol levels in breast muscle compared to the control. The combination of antioxidants in the +ECSe group raised GPx activity in whole blood compared to the control. In conclusion, results indicated that vitamin E is the most effective antioxidant to alleviate oxidative stress caused by high dietary PUFA and that the supplementation with additional vitamin C and selenium did not have clear synergistic effect.