Legumes have unique mechanisms to respond to nutrient deficiencies that can be considered as important advantages for agricultural purposes. The preponderance of plant-based protein is on the rise, and the market value of protein crops is expected to be worth billions by 2025. To match the global demand for plant-based products, crops productivity must be ensured; however, this might be impaired either by environmental or anthropogenic pressures that lead to soil nutrient disturbance. The responses activated by legumes to nutrient deficiencies and the mechanisms they utilize to adapt to such conditions will be discussed in this chapter. The study of these factors enables breeding programs specific for legumes and crop improvement. Understanding legumes responses also allows for a better management of agricultural practices and the adoption of more sustainable methods. It is important to reflect on the impact of climate change and intensive farming on food quality and on the future of agriculture, and this chapter contributes with important facts about the role of legumes in our current scenario.