Silicon (Si) is a mineral element that is well known to protect plants against several environmental changes. While the exact mechanism is not known, beneficial responses across a broad range of crops highlight Si’s role in maintaining internal homeostasis. All plants accumulate Si to either macro- or micro-nutrient concentrations. This allows Si to work as a biostimulant due to its ability to reduce abiotic stresses including osmotic and nutritional imbalances. This chapter focuses on the function of Si in the context of abiotic stress reduction and growth promoting factors in plants.