An experiment was conducted to determine the effect of varying dietary supplemental inclusion levels of onion and garlic on semen quality characteristics of Hubbard white breeder broiler cocks aged 35-41 weeks old. A complete randomized design was used for the experiment. The three dietary supplemental levels based on garlic and onion supplemental inclusion levels are L 0 (0g onion and 0g garlic per 600g DM feed), L 1 , (2.5g onion and 2.5g garlic per 600g DM feed) and L 3 (5g Onion and 5g garlic per 600g DM feed) with each treatment having 3 replicates. A quadratic type equation was used to determine the Onion and Garlic levels for optimum semen quality characteristics. Daily supplementation with 2.5g onion and 2.5g garlic per 600g DM feed increased (P<0.05) actual life sperm count (×10v /nl) by 370.58 % whereas daily supplementation with 5g onion and 5g garlic per 600g DM feed increased (P<0.05) actual life sperm count (×10v /nl) by 405.75%. Similarly, daily supplementation with 2.5g onion and 2.5g garlic per 600g DM feed increased (P<0.05) live sperm count (%) by 399.88 % whereas daily supplementation with 5g onion and 5g garlic per 600g DM feed increased (P<0.05) live sperm count (%) by 379.90%. Dietary onion and garlic supplemental inclusion levels of 3.335g, 3.446g, 3.787g, 3.438g, 3.068g, 4.247g per 600g DM feed supported optimum actual dead sperm count, dead sperm count, actual live sperm count, live sperm count (%), acrosome morphology defects (%), acrosome detachment (%) with probability values ranging from 0.018 to 0.906, whereas minimum Acrosome abnormality (%) reduction was achieved at an optimum supplementation level of 3.58g per 600g DM feed with Y=3.33-1.332x+0.186x 2 , r 2 = 0.680, P-value = 0.018. These findings show that onion and garlic supplementation enhances semen quality characteristics in Hubbard white breeder broiler cocks.