Forty-eight male albino rats, aged 12–14 weeks and weighing 200–250 g, were used to assess the protective nano lutein effects on the male reproductive system from oxidative stress conditions. The experiment, conducted in the animal house of the Department of Biology, College of Education, University of Al-Qadisiyah, consisted of dividing the rats into six groups (n = 8 per group): a control group administered drinking water only; T1, administered 1% hydrogen peroxide (H₂O₂); T2, treated with normal lutein (48 mg/kg); T3, treated with nano lutein (24 mg/kg); T4, administered H₂O₂ and normal lutein; and T5, treated with H₂O₂ and nano lutein. Experimental period was 45 days.Results revealed that there was a significant reduction (P < 0.05) in serum testosterone, LH, and FSH levels of T1 rats treated with H₂O₂ only, as well as sperm concentration, motility, viability, and normal morphology. However, treatments T2 and T3 were not different from the control group, suggesting that lutein—normal and nano—did not exert any adverse effect on reproductive parameters. Interestingly, T4 and T5 groups (treated with H₂O₂ and either form of lutein) exhibited significant (P < 0.05) improvement in hormone profile and sperm quality when compared with T1, indicating a protective effect. Although T5 showed a greater improvement in results, the difference between T4 and T5 was not significant. The findings support nano lutein's antioxidant action in inhibiting oxidative damage in male reproductive function.