Pepper is an important commercial crop, cultivated for vegetable, spice, and value-added processed products. Irrigation is essential for pepper production because pepper is considered one of the most susceptible crops to water stress in horticulture. The physiological responses of plants to water stress and their relative importance for crop productivity vary with species, cultivars, soil type, nutrients, and climate. Drought is considered as the main constraint on the extension of cultivated lands and the increase of crop production in many parts of the world. To optimize pepper production and profitability in drought conditions, and to ensure the most efficient use of limited water resources, there is a clear need for comprehensive information regarding crop water use of pepper grown under deficit irrigation (DI) systems. The decline in water availability for irrigation and the positive results obtained by DI in some fruit crops have improved the interest in developing information on DI for a variety of crops.