In recent decades, the agricultural sector has faced numerous challenges. Population growth, increasing food demand, climate change, and the environmental consequences of excessive chemical input use have seriously threatened the sustainability of crop production. In this context, the utilization of amino acids as substitutes or supplements for conventional fertilizers represents an innovative approach to improving production sustainability and enhancing plant adaptation to climatic stresses. Amino acids, as organic nitrogenous compounds and the building blocks of proteins, play fundamental roles in regulating plant physiological and biochemical processes and have recently attracted attention as biostimulants. The aim of this review article is to elucidate the role of amino acids in improving plant growth, yield, and stress tolerance. The methodology of this study is based on a literature review and the examination of research conducted using reliable scientific sources, databases, and content analysis of specialized articles and books. Research findings indicate that the application of amino acids improves growth and photosynthetic indices and, through enhanced nutrient uptake, increased antioxidant enzyme activity, and regulation of osmotic balance, strengthens plant tolerance against stresses such as drought, salinity, and unfavorable temperatures. Additionally, amino acid use can enhance yield and certain quality parameters of crops and enhance the long-term stability of the soil. Overall, the targeted application of amino acids can reduce dependence on chemical fertilizers, providing an effective step toward sustainable agriculture and improved productivity in plant production systems.