The effects of safflower oil and/or vitamin C (Vit. C) inclusion in broiler chicken diets on the growth performance, apparent ileal digestibility coefficient “AID%” of amino acids, intestinal histology, behavior, carcass traits, breast muscle fatty acid composition, antioxidant and immune status for a 35-day feeding period were evaluated. A total of 300 three-day-old Ross chicks (58.25 g ±0.19) were randomly allotted in a 2x3 factorial design consisting of two levels of vitamin C (0 and 400 mg/kg diet) and three levels of safflower oil (0, 5, and 10 gm/kg diet). Results: An increase in the final body weight, total body weight gain, total feed intake, and the relative growth rate (P < 0.05) were reported by safflower oil and/or vitamin C inclusion. Dietary supplementation of safflower oil and/or vitamin C had a positive effect (P < 0.05) on the ingestive, resting, and feather preening behavior. Vitamin C supplementation increased (P < 0.05) the AID% of lysine, threonine, tryptophan, arginine, and valine. Safflower inclusion (10 g/kg) increased (P < 0.05) the AID% of methionine and isoleucine. Safflower oil inclusion increased (P < 0.05) the levels of stearic acid, linoleic acid, saturated fatty acids, and omega-3 fatty acids (ω-3) in the breast muscle, while the supplementation of only 10 g of safflower oil/kg diet increased (P = 0.01) the omega-3/omega-6 (ω-3/ω-6) fatty acids ratio. Vit. C supplementation increased (P < 0.05) the serum levels of the CAT, SOD, and GSH enzymes. Dietary supplementation of safflower oil and/or vitamin C improved the intestinal histology and increased the villous height and width, crypt depth, villous height/crypt depth ratio,mucosal thickness, goblet cell count, and intra-epithelium lymphocytic lick cells infiltrations. The serum levels of IgA and complement C3 were increased (P < 0.01) by Vit. C supplementation and prominent in the 400 vit.C + 10 safflower Oil group. Conclusion: A dietary combination of safflower oil and vitamin C resulted in improved growth rate, amino acids AID%, intestinal histology, welfare, immune and antioxidant status of birds, and obtaining ω-3 and linoleic acid-enriched breast muscle. The best inclusion level was 400 vit.C+10 safflower Oil.