This study aimed to evaluate the National Program for Vitamin A Supplementation in a municipality (county) in Northeast Brazil, with participation by the parents or guardians of children under five years of age. This was a cross-sectional, population-based study using both qualitative and quantitative approaches. A total of 657 interviews were performed, and the vitamin A doses recorded on the children’s immunization cards were analyzed. The population has access to high doses of vitamin A. However, knowledge of the vitamin A supplementation program was limited, especially among parents with less schooling. The program’s coverage fell short of the Ministry of Health’s target, especially after 18 months of age. It is thus necessary to intensify the program’s educational activities in order to raise awareness among families of under-five children on the importance of vitamin A, its supplementation, and the importance of eating natural sources of this nutrient for the child’s health.