Citriculture is a primary agricultural product in Morocco, where water scarcity is a significant challenge exacerbated by climate change. This four-year study investigated the impact of deficit (50% of crop evapotranspiration, ETc) and excessive (150% ETc, and 200% ETc) irrigation on Esbal clementine quality in the Souss-Massa region of Morocco. Four irrigation treatments (50%, 100%, 150%, and 200% ETc) were applied to evaluate their influence on fruit size, acidity, and Brix degree, which measures the dissolved sugar content in a liquid solution. Results indicate that excessive irrigation (200% ETc) increased fruit size by 108% but decreased the Brix degree by 46%. Conversely, deficit irrigation (50% ETc) led to a smaller fruit size, yet maintained higher Brix values. Fruit acidity remained relatively stable across treatments, with values ranging from 2.53% in 2019 to 1.54% in 2022 under deficit irrigation (50% ETc) and showing no significant differences between deficit and excessive irrigation strategies. These findings contribute to understanding the balance between water use and fruit quality, informing sustainable irrigation strategies for citrus production in water-scarce regions.