This study evaluated the effects of graded dietary niacin supplementation on performance, egg quality, and yolk antioxidant capacity in laying quails. A total of 180 birds were assigned to six treatments (0, 10, 20, 40, 80, and 120 mg/kg niacin) for 12 weeks under a completely randomised design. The control diet contained 25.32 mg/kg niacin. Niacin supplementation produced modest but statistically significant effects on certain productive performance (P < 0.05). Egg production and egg mass improved up to 40 mg/kg, showing linear trends (P = 0.034 and P = 0.022, respectively), while feed conversion ratio was most efficient at the same level (P = 0.040). Supplementation with 10 mg/kg enhanced shell strength (P = 0.034) and thickness (P = 0.030), indicating a dose-specific response at low inclusion. Internal egg quality (albumen index and Haugh unit) increased linearly (P ≤ 0.001), reaching their highest values at 120 mg/kg. Yolk antioxidant capacity (DPPH) rose by 26.8%, whereas lipid peroxidation (MDA) declined by 55% at 120 mg/kg (both P < 0.05). Overall, niacin influenced productivity and antioxidant status in a dose-dependent but non-linear manner, suggesting distinct optimal levels for performance (40 mg/kg) and oxidative protection (120 mg/kg). Further long-term and large-scale studies are warranted before revising niacin recommendations for laying quails.