This research was conducted to determine the effect of quinoa seed (Chenopodium quinoa Willd.) extract on the performance, carcass parameters, and meat quality in Japanese quails. In this study, 400 quail chicks were divided into a control group (without quinoa seed extract addition) and 3 experiment groups (4 replicates containing 25 quails in each). Commercial feed and the addition of different concentrations of quinoa seed extract (QSE) 0.1 g/kg, 0.2 g/kg, and 0.4 g/kg were used in the study. During the second week of the experiment, the highest feed intake was obtained from the supplemented groups (p < 0.01). After 5 weeks of experimentation, the highest feed consumption was noticed in the group with 0.4 g of QSE additive. The QSE additive affected the live weight gain values of all experimental groups during 1 week of the experiment. The highest values of hot carcass weight were noticed in groups with 0.2 and 0.4 g of QSE additive (p < 0.01). While the highest value of cold carcass weight was noticed in a group with 0.2 g of QSE additive (p < 0.05). Thigh, breast, back and neck ratio, and internal organs (except gizzard) were not affected by the supplementation of QSE. As a result of storage of breast meat at 4 °C for 0, 1 days, 3 days, 5 days, and 7 days, it was determined that the number of pH, thiobarbituric acid, peroxide, and total psychrophilic bacteria were lower in the groups with QSE as compared to the control group (p < 0.05). In conclusion, the best results of quail performance were obtained with 0.2 g/kg and 0.4 g QSE/kg of the quail’s fodder. While the addition of 0.4 g QSE/kg of the quail’s fodder had a significant effect on meat shelf life and could be used in poultry mixed feed to prevent or delay lipid oxidation of meat.