A total of 300 unsexed one-day-old Japanese quail chicks (Coturnix coturnix japonica) were used in a 3x2 factorial arrangement. Quail chicks were randomly divided into three treatment groups (100 chicks/ group) that received three dietary protein levels (20, 22 and 24 % CP). Each quail group was randomly divided into two sub-groups (50 chicks each). The first sub-group of each group received diet without any supplementation, while the second sub-group was given diets supplemented with Vitamin E (VE) 200 IU and Selenium (Se) 0.5 mg/kg diet. The experimental diets were formulated isofibrous and isocaloric (2900 kcal ME/kg). The main results obtained could be summarized as follows: - Live body weight and body weight gain were improved with the medium protein level (22%) followed by high protein (24%) and the low protein level (20%) during the whole experimental period. - Feed intake during the whole experimental period recorded significantly (P<0.05) increased with decreasing dietary crude protein level. In contrast, protein intake recorded significantly decrease (P< 0.05) with decreasing CP level. - Feed conversion ratio revealed significantly (P<0.05) improved with medium protein level in the diet. - Efficiency of protein utilization was improved with low protein level 20% in the diet. - Morality rate recorded non-significant difference among experimental groups of protein level. - Dietary protein level had insignificant effect on carcass traits. - Digestibility coefficients and the nutritive values expressed as DCP, TDN % and ME kcal/kg were significantly varied (P<0.05) among different protein levels. - Economical efficiency percentage recorded higher values with 22% protein level. - Regardless of protein level, results showed that supplementing diet with VE and Se affected of body weight, body weight gain, feed conversion ratio and morality rate were significantly (P<0.05) improved, but feed consumption was significantly increased (P<0.05), while efficiency of protein utilization improved as compared to unsupplemented diets. - Carcass traits were improved clearly when quail fed a diet contain 22 % level of protein supplemented with VE and Se.   - Digestibility coefficients and the nutritive values expressed as DCP, TDN % and ME kcal/kg were significantly improved (P<0.05) with VE and Se as compared to unsupplemented diets. - Economical efficiency percentage recorded the higher values when supplementing diet with VE and Se. - Interaction between dietary protein level, VE and Se supplementation indicated that the presence of supplemented with any level of dietary protein resulted in improvements in the obtained values of live body weight and body weight gain, feed conversion, carcass traits, digestibility trials and economical efficiency comparably with the unsupplemented diets during the experimental period. - The higher value of economical efficiency was obtained by using 22% CP with Supplemented VE and Se compared to other treatments. From the previous results, it could be concluded that moderate protein level 22 % in diet supplemented with Vitamin E and Selenium (200 IU VE and 0.5 mg Se /kg diet) improve the growth performance of growing Japanese quail and the economic efficiency.