AbstractMalnutrition in all its forms is a global problem, with the worst effects felt in developing countries. The importance of producing food to improve nutrition security is self‐evidently a promising approach to combating malnutrition. The present study assessed the nutritional quality response of orange‐fleshed sweet potato (OFSP) varieties to deficit irrigation (DI). The study's specific objectives were to (i) evaluate yield and root quality and (ii) assess the nutritional root yield and nutritional water productivity of selected OFSP varieties under full and DI. Beta‐carotene, iron, and zinc were the root quality parameters studied. A factorial arrangement of treatments was laid out in a randomized complete block design (RCBD). The irrigation rates used for scheduling were 100% (full irrigation), 60% (60 [DI]), and 30% (30 [DI]) of total available water (TAW). The test varieties were Naspot‐13 and Jewel of the OFSP crop. The beta‐carotene content of the Jewel cultivar was 27% higher than that of the Naspot‐13 cultivar. However, neither cultivar's root quality changed under DI. The results show that serving 125 g of boiled OFSP varieties provides more than 100% of vitamin A, sufficient iron, and minimal zinc dietary requirements for 4‐ to 8‐year‐old children and 10‐ to 50‐year‐old pregnant women. In general, the nutritional water productivity of root quality parameters increased with a decrease in water application. In conclusion, a positive water‐food‐nutrition nexus was established under the Naspot‐13 variety, suggesting a capacity for alleviating vitamin A, iron, and zinc deficiency health‐related problems, particularly in children and pregnant women in regions with limited water resources. Therefore, adoption of DI strategies for underutilized crops using smart pressurized irrigation systems could be significant in undertaking water management reforms.