Water scarcity remains a significant challenge for global agriculture. Deficit irrigation has emerged as a strategy to optimize water productivity without compromising crop yield. This study aimed to assess the impact of deficit irrigation on tomato yield and water productivity (WP). Two field experiments were conducted over consecutive seasons of 2022 and 2023 using drip irrigation. Three irrigation regimes were employed: 100% (T100), 75% (T75), and 50% (T50) of the full irrigation requirements. Crop stress indicators, including fresh biomass weight (FB), dry-biomass weight (DB), canopy water content (CWC), soil moisture content (SMC), and relative chlorophyll content (SPAD measures) were evaluated. The results showed that the highest values of FB, DB, CWC, SMC, and yield were achieved under T100, followed by T75, while the lowest values were observed at T50. The highest SPAD values were obtained under T75, followed by T100 and T50 for both seasons. The results further showed that the highest WP values were observed with T100 (27.37 kg/m³), followed by T75 (25.96 kg/m³). The lowest WP value was 21.58 kg/m³ at T50. The application of T75 and T50 led to saving 22.29% and 44.57% of the irrigation water applied compared to T100 in both seasons, respectively. In conclusion, this study proves that applying moderate deficit irrigation at T75 is considered to be a feasible technique for tomato production.