To investigate the effects of nano-oxide zinc (ZnO NPs), spirulina platensis (SP), and their combination on broiler chickens' growth, carcass traits, blood biochemistry, and redox status. A total of 270 Cobb broiler chicks that were one-day-old were allocated into nine equal groups at random. The first group was given a basal diet and functioned as a control group. The other groups were given the basal diet supplemented ZnONPs with 30 or 60 mg/kg diet (groups 2 and 3) or SP with 2 or 4 g/kg diet (groups 4 and 5), and their combination (groups 6 to 9). Results showed that supplementation with ZnONPs and SP, individually or combined improved daily body weight gain (BWG) and live body weight (LBW). This increase in LBW was associated with reduced feed consumption (FC), leading to an improved feed conversion ratio (FCR). The best outcomes were observed with the higher dose of ZnO NPs (60 mg/kg) or its combination with 4 g/kg SP. High doses of ZnONPs and SP significantly (P≤0.05) reduced abdominal fat and increased relative carcass weight. ZnONPs also improved hemoglobin content and red blood cell count. No significant differences were found in plasma total protein, albumin, globulin, or glucose levels, but liver enzyme activities (AST and ALT) significantly (P≥ 0.01) decreased. Plasma total lipids and triglycerides decreased slightly with ZnONPs or SP supplementation. The activity of the antioxidant enzymes total antioxidant capacity (TAC), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT) were increased, while malondialdehyde (MDA) levels showed a slight decrease. serum immunoglobulins (IgA, IgM, IgG, IgD, and IgE) were boosted in treated groups, with significant increases (P≤0.05) in IgG, IgD, and IgE with the ZnONPs + SP groups. In conclusion, ZnONPs, SP, and their combination enhanced broiler performance, blood biochemical balance, and antioxidant status, with the best results achieved at 60 mg ZnONPs combined with the two studied levels of SP.