Decision Trees are a decision support tool that uses a tree-like graph of decisions and their possible consequences. Each node in the tree represents a decision point or a test on an attribute, each branch represents the outcome of the decision, and each leaf node represents a class label or a final decision. Decision trees are used for both classification and regression tasks, providing a visual and interpretable model of decision-making processes. They are easy to understand and implement, making them popular in various applications such as medical diagnosis, credit scoring, and customer segmentation.