Because the use of antibiotics as growth promoters was banned due to global health concerns, researchers are focusing on exploring alternative safe and effective feed additives. Rare earth elements (REEs) are located in group III of the periodic table, which includes cerium (Ce), lanthanum (La), and other elements. Recently, REEs have been involved in many medical, industrial, zootechnical, and agricultural applications. They play a pivotal role in functional and structural molecules in the biological system. Currently, in veterinary practice, REEs have been introduced as new feed additives to improve animal health and production. Based on the previous literature, REEs reportedly enhance milk, egg, and meat production. However, the controversy between adverse (e.g., toxicological and ecotoxicological) and favourable REE-associated effects has not been fully discussed. This review summarizes the relevant literature on the impacts of REEs on animal production and health; specifically, this review emphasizes the application of REEs as alternative safe feed additives used to promote animal growth and performance.