Aquaponic system is one of the modern systems that have been used to make the most of the water, in addition to integrating the agriculture of plants and fish together in one production system. It is an innovative, sustainable technology and environmentally friendly. The main objectives of this study are to evaluate the growth performance of Nile tilapia under the aquaponic system for a period of 42 days and to examine the effect of system type (aquaponic and hydroponic systems) and water flow rate of (0.5, 1.5 and 2.5 L/min) on the growth performance of lettuce plants grown in deep water culture technique (DWC) and nutrient film technique (NFT). The obtained results for fish indicated that fish weight, fish length and feed conversion ratio (FCR) were increased during the experimental periods. The results obtained for lettuce plants indicated that root length of the lettuce gradually increased with increasing water flow rates and growth period. the root growth rate was higher in aquaponic system than in hydroponic system. The nutrients consumption rate, water use efficiency and lettuce yield were increased with an increase in the water flow rate from 0.5 to 1.5 L/min and a decrease in the water flow rate from 1.5 to 2.5 L/min. The former parameters were higher in the hydroponic system than in the aquaponic system except for the rate of sodium consumption. The hydraulic loading rate was increased with increasing the water flow rate while the nutrient uptake time decreased with increasing the water flow rate.