Objective: Rapid development in low- and middle-income countries (LMIC) has led to changes in diet that have outpaced water and sanitation improvements, contributing to a dual burden of overweight and noncommunicable disease risk factors (OWT/NCD) and undernutrition and infectious disease symptoms (UND/ID) within individuals and households. Yet, little work has examined the joint impact of water and food exposures on the development of the dual burden. Methods: We use data from Ecuador's nationally representative Encuesta Nacional de Salud y Nutrición (ENSANUT-ECU) to test whether water access and quality and diet quality and security are associated with OWT/NCD and UND/ID among 1119 children and 1582 adults in Galápagos. Adjusted multinomial and logistic models were used to test the separate and joint associations between water and food exposures and the dual burden and its components at the individual and household levels. Results: The prevalence of the dual burden of OWT/NCD and UND/ID was 16% in children, 33% in adults, and 90% in households. Diet quality was associated with a higher risk of dual burden in individuals and households. Mild food insecurity was positively associated with the risk of dual burden at the household level. No water variable separately predicted the dual burden. Joint exposure to poor water access and food insecurity was associated with greater odds of dual burden in households. Conclusion: Our results suggest that unhealthy diets and poor water quality contribute to the dual burden at the individual and household levels. Addressing both food and water limitations is important in LMIC.