The impact of cowpea protein hydrolysate (CPH) dietary supplementation was assessed on the growth performance, blood hematology, liver histomorphology, antioxidant status, and inflammatory responses in broiler chickens. Five hundred 3-d-old broiler chickens (88.72 g ± 0.20) were assigned to 5 experimental treatments (10 replicates/treatment), the basal diet supplemented with 5 inclusion rates of CPH: 0, 2, 4, 6, or 8 g/kg. Throughout the experimental periods, broiler chickens fed diets supplemented with CPH showed no change in the growth rate. The 2 g CPH/kg treatment increased the red blood cell count, hemoglobin concentration, packed cell volume percentage, white blood cell count, and lymphocyte count (linear, P < 0.01; quadratic, P < 0.05). Uric acid concentration increased in the CPH-supplemented treatments (linear, P = 0.031). The inclusion of CPH reduced the total cholesterol (Linear, P = 0.03; quadratic, P = 0.02), the low-density lipoprotein concentrations (linear, P = 0.012), and the triglyceride concentrations (linear, P = 0.01). Dietary supplementation of CPH increased the total antioxidant capacity, catalase (linear, P < 0.001), and superoxide dismutase activity (linear, quadratic, P < 0.01). Supplementation of CPH showed a down-regulation of the expression of caspase-3 antibodies in the liver tissues (Linear, P < 0.01). Liver histoarchitecture was normal in all experimental treatments. It can be concluded that dietary cowpea protein hydrolysate can be used as a potential protein supplement inbroiler chicken diets to improve antioxidant status and lower the blood lipids without affecting the broiler chickens’ growth rate.