The present study evaluated the growth performance and whole-body composition of the hybrid red tilapia (Oreochromis mossambicus × O. aureus) raised in saltwater and fed three experimental diets containing different protein levels (25.6, 30.8 and 35.6% CP; crude protein). The hybrid red tilapia showed a high production performance across all dietary treatments: specific growth rate (SGR) = 3.12-3.51% body weight d-1; weight gain = 391-503%; feed conversion ratio (FCR) = 0.90-1.07; thermal growth coefficient (TGC) = 1.50-1.67; condition factor (CF) = 0.19-0.26. Dietary protein content significantly affected feed intake; fish fed the 30.8% CP diets displayed higher feed intake than those fed the 25.6% CP diet. Although the protein efficiency ratio (PER) was not significantly affected by dietary treatments, fish fed 25.6% CP diet demonstrated numerically higher values than those fed the other dietary treatments (4.34 vs. 3.06-3.35). The viscerosomatic index was significantly reduced in the 25.6% CP group compared to 30.8 and 35.6% CP groups. Regarding the whole-body composition, dietary protein affected all parameters, except lipid content. Fish fed the 30.8% CP diet exhibited significantly reduced relative protein content and elevated ash content in the whole-body in comparison to other dietary groups. The results of the present study indicated that juveniles of hybrid red tilapia accepted all dietary treatments. However, according to polynomial regression analyses based on PER and the high ash content in tilapias fed the 30.8% CP, it is suggested that the optimum dietary protein content for juvenile hybrid red tilapia was 25.6%.