Eight essential micronutrients—B, Cl, Cu, Fe, Mn, Mo, Ni, and Zn—are critical for healthy plant growth. Deficiencies in these trace elements can severely affect yield and quality, varying across crop species and regions. Zinc deficiency is the most widespread, followed by boron. Iron and copper deficiencies are regionally significant. The chapter outlines how agricultural intensification and soil management have increased micronutrient deficiencies and emphasizes the need to balance soil nutrient concentrations to avoid both deficiency and toxicity. The role of crop varieties in micronutrient efficiency and typical deficiency symptoms are discussed.