Women’s adequate nutrition before and during pregnancy and lactation is crucial to ensure maternal health, optimal fetal development and it may also determine long-term offspring’s health. In fact, pregnancy malnutrition — either by  deficiency or excess — is considered a putative fetal programmer of adult disease. This chapter explores the relevance of micronutrients in the maternal setting, focusing on micronutrients that raise public concern given the prevalence of their deficiencies in pregnancy (iodine, iron, zinc, folate, and vitamin A) and on others also relevant for maternal and offspring’s health (vitamins B12, C, and D). Food sources and biological functions will be presented as well as the role of micronutrients as determinants of pregnancy outcomes and fetal and offspring growth and health. Deficiency prevalence, guidelines for dietary intake and supplementation, the relevance of well-planned diets during susceptible periods of life are also addressed and topics under debate and warranting further research are highlighted.