The current study investigates the possablities to improve irrigation water productivity of tomato crop, as one of the most important vegetable crops in Egypt, by applying different deficit irrigation scheme . Field experiment was carried out at the Vegatable Farm of the Faculty of Agriculture- Ain Shams University, througthout two seasons 2015/2016 and 2016/2017, on tomato crop under drip irrigation system. Five irrigation treatments, included: (i) 100% ETc [T100], (ii) Application of deficit irrigation level 80% ETc at all crop growing stages [TC80], (iii) Application of deficit irrigation level 80% ETc at initial and maturity crop stages only [TS80], (iv) Application of deficit irrigation level 60% ETc at all crop growing stages [TC60], (v) Application of deficit irrigation level 60% ETc at initial and maturity crop stages only [TS60]. The results showed that, among the investigated deficit irrigation schemes, applying diffecit irrigation schemes of 80% ETc could reduce the amount of the irrigation water by 20% when it was applied at all crop growing stages, coupled with a yield reduction of about 17%, and a slight increase in water productivity [WP] (dividing dry matter of the yield to the ETc) by about 2%. Whereas the same deficit level could save about 16% of the applied water when it was applied only at initial and maturity growth stages, and decreased the crop yield by 5%, which gave the highest WP of 2.15 kg/m3, compared to the other investigated irrigation treatments. Regarding the AquaCrop model simulation, the results showed that, considering good calibration process, AquaCrop model revealed a very good performance in simulating the tomato crop biomass, and yield. This could encourage addressing AquaCrop model as a good tool that can be used with a high degree of reliability in practical management, strategic planning of irrigation, and water limited conditions in Egypt.