A feeding trial was conducted to investigate the effect of replacing Soybean meal (45% Crude Protein) with Wolffia meal (45% Crude Protein) at 0%, 25%, 50%, 75% and 100% inclusion levels in the practical diets of Genetically Improved Farmed Tilapia (GIFT) juveniles. One hundred and fifty (150) juveniles of GIFT with initial mean weight of 6.86 ± 0.20 g were stocked randomly into fifteen (15) glass aquaria tanks at 10 fish/tank in five treatments with three replicates each. The experimental diets were iso-nitrogenous (40% Crude Protein) and iso-caloric (11.1kcal/kg). Using a complete randomized design, each diet was fed to the test fish for 70days. The highest weight gain was recorded in the fish fed D5 (25.74±0.30)g containing 100% inclusion level of Wolffia meal and the least weight gain was in the fish fed D1(13. 50±0.20) with 100% inclusion level of Soybean meal. Specific growth rate (SGR) ranged from 0.67 ± 0.01 (D1) to 0.97 ± 0.07 (D5). Feed conversion ratio (FCR) was significantly (P> 0.05) different among the treatments (D1 - D5) with the least value in D5 (1.94± 0.02); protein efficiency ratio (PER) and net protein utilization (NPU) values were significantly (P> 0.05) highest (6.44 ±0.08 and 1.50±0.06) % respectively in fish fed D5. The overall results indicated that 100% replacement of Soybean meal with Wolffia Meal in the diets of Genetically Improved Farmed Tilapia juveniles gives optimal feed utilization without compromising fish growth