Objective. The current research investigated the effects of dietary biotin supplementation on performance, egg quality, and yolk antioxidant capacity in laying quails. Material and methods. A total of 150 female quails (11 weeks old) were assigned to five dietary groups, receiving 0, 0.075, 0.150, 0.300, or 0.450 mg/kg of biotin over 70 days. Results. Biotin supplementation linearly decreased body weight while increasing egg production in quails (p<0.01). Eggshell-breaking resistance improved quadratically, peaking at 0.300 mg/kg (p<0.01). Yolk index declined quadratically, whereas yolk colour parameters (L* and a*) and antioxidant status (DPPH and MDA in yolk) responded linearly to biotin levels (p<0.01). Conclusions. The findings suggest that biotin requirements for laying quails exceed current recommendations, with an optimal range of 0.300–0.450 mg/kg for both performance and antioxidant properties.