Currently, sustainable development is a dominant global trend, significantly impacting food technology. One of the solutions is the valorization of valuable agricultural by-products generated in food production, such as those from vegetable oil and fruit juice production. Alfalfa (Medicago sativa L.) is a perennial herbaceous plant belonging to the legume family (Fabaceae). It is widely cultivated for forage and as a cover crop with high protein content. Alfalfa protein is highly valued in the food and feed industry for its rich nutritional value and multifunctionality. To align with sustainable development, current protein extraction methods focus on minimizing environmental impact by using environmentally friendly solvents and techniques, known as green extraction methods. One promising green extraction method is the use of ionic liquids (ILs), which are composed of an organic cation and either an organic or inorganic anion. Their unique properties, such as low vapor pressure, high thermal stability, and the ability to dissolve various substances, make them environmentally friendly alternatives to conventional solvents. Using ILs in protein extraction processes offers high yields and purity while adhering to green chemistry principles. Therefore, this chapter provides detailed protocols for the extraction of protein from alfalfa leaves using ionic liquids for use in food, beverages, and beyond.