National reports highlight inadequate intakes of vitamin D and iron among Irish children, aged 1- to 5- years, two nutrients that are pivotal for optimal growth in early childhood. Considering the vital role of parents in shaping dietary habits, this project aims to explore parents’ awareness and perceptions of vitamin D and iron in diets of their children and compliance with supplementation recommendations arising from new Department of Health Healthy Eating Guidelines for 1-to-4-year-olds. This PhD project will identify the gaps in parental knowledge of these micronutrients and assess adherence to current iron and vitamin D supplementation polices among young children. The findings of this project will inform future health promotion campaigns to support parents establish good eating and supplementation practices to help achieve optimal intakes of iron and vitamin D for this vulnerable age group.