This experiment was performed to investigate the impact of a partial substitution of 0, 10, 20, and 30% of dietary soybean meal (SBM, 43.76 % CP) by an equal portion of Oriental Hornet Meal (OHM, 76.84% CP). Forty weaned Ossimi male-lambs were assigned to four equal groups, nominated as T1 (control, 0% OHM), T2 (10% OHM), T3 (20% OHM), and T4 (30% OHM), respectively. The study lasted four months for the growth experiment, then continued until lambs reached puberty. The results showed that when lambs were fed diets containing OHM, the digestibility coefficients of dry matter, organic matter, crude protein, and nutritional values such as total digestible nutrients and digestible crude protein were considerably (P<0.01) higher than for control. Moreover, the final body weight and average daily gain of lambs fed OHM diets were significantly (P<0.01) higher compared to those fed control diet. In addition, lambs fed OHM-containing diets had a considerably greater ruminal concentration of volatile fatty acids (T2: 5.51, T3: 5.74, T4: 5.98 vs T1: 5.16 ml eq / 100 ml), greater counts of protozoa cells (T2: 1.33, T3: 1.45, T4: 1.67 vs T1: 1.22 x10(6) /ml rumen fluid) and lower concentrations of ruminal NH3-N (T2: 23.51, T3: 21.59, T4: 18.27 vs T1: 28.49 mg / 100 ml) versus the control diet, respectively. The levels of serum total protein, glucose, and thyroid hormones were significantly (P<0.01) higher by increasing OHM inclusion level, while low-density lipoprotein concentration was decreased (T2: 109.02, T3: 108.16, T4: 109.57 vs T1: 110.22 mg/dl). Liver and kidney functions were unaffected by groups. Moreover, the results revealed that all examined puberty parameters and the majority of semen characteristics significantly improved (P<0.001 and P<0.05) with the substitution of up to 30% of SBM with OHM, respectively. In conclusion, OHM improved the Ossimi lambs' performance, it is safe and recommended to be used.