A decision tree is a model that makes predictions by learning a series of if-then rules from data, splitting the data at each step on the feature that best separates the classes. It resembles a flowchart: start at the root, answer a question, follow the branch, repeat. Decision trees are highly interpretable — you can visualize every decision path — making them popular in regulated industries like banking. A Moroccan bank might use one to decide loan approval based on income, age, and employment history.