Children are at high risk of nutritional anemia with a global prevalence of 42% in children <5 years of age. Iron deficiency anemia (IDA) is the most common cause of nutritional anemia in children and is associated with poor neurodevelopmental outcomes. There are large, physiological changes in biomarkers of iron status during early childhood, so age-specific reference intervals are needed. In order to prevent nutritional anemias, delayed umbilical cord clamping should be practiced, infant formula should be fortified with iron and other micronutrients, low birth weight infants should receive iron supplements, infants from 6 months of age and toddlers should receive an iron-rich diet, and adolescent girls should be screened for iron deficiency (ID). In areas with a high prevalence of anemia, iron supplements or point-of-use fortificants should be considered and infections should be prevented and treated. Excessive iron intakes in young children may cause adverse effects, so iron interventions should be targeted to high-risk groups.