Abstract. Supplements derived from plants are utilized to maintain and promote the growth efficiency of animals. The use of black pepper oil (BPO) has recently generated significant scientific interest, primarily because of its potential beneficial effects on both humans and animals. The goal of the current study was to determine how dietary BPO supplementation affected growth performance, characteristics of growing quails’ immunity, antioxidant status, and carcass yield. A total of 240 growing quails (1 week old) were divided into five equal groups, each with 36 birds (four replicates of 12 each). A basal diet containing no BPO (0 gkg􀀀1) was given to the first group, and the second, third, and fourth groups were given a diet that was supplemented with BPO (0.4, 0.8, 1.2, and 1.6 gkg􀀀1, respectively). In comparison to a control group, quails’ diets that were supplemented with 0.8 g BPO kg􀀀1 showed improvements in final live body weight, body weight gain, and feed conversion ratio of 10.68 %, 12.6 %, and 18.2 %, respectively. During the whole study period (1 to 5 weeks), quails fed diets with 0.8 g BPO consumed less feed than the other groups and control. Due to BPO treatment, there were no statistically significant changes in any of the carcass parameters. BPO-supplemented groups had significantly elevated plasma levels of albumin and globulin than control groups (P <0.05), but the albumin=globulin ratio was reported to be significantly decreased (P <0.05) in birds supplemented with diets containing BPO compared to the control group. When compared to the control, the liver enzyme activity (aspartate transaminase (AST) and alanine transaminase (ALT)) in blood plasma was reported to be significantly increased in the quails given 0.4 and 0.8 g BPO kg􀀀1. Glutathione and catalase activities were significantly higher in the group given diets supplemented with BPO (1.2 gkg􀀀1) than they were in the control group. In comparison to the control, the supplementation of BPO in the diets of quail significantly enhanced (P <0.05) the lipid profile in the plasma, moreover decreasing the caecal content pH (P <0.05). In comparison to the control, the populations of lactobacilli, coliform, Salmonella spp., and Escherichia coli in the caecum significantly decreased in the BPO-supplemented groups (P <0.05). In conclusion, dietary BPO supplementation in Japanese quails’ diet can boost growth performance and antioxidant indices, enhance lipid profile and carcass traits, and reduce intestinal infections.