A B-Tree is a self-balancing tree data structure that maintains sorted data and allows for efficient insertion, deletion, and search operations. It is commonly used in databases and file systems to manage large amounts of data. Each node in a B-Tree can have multiple children, which helps to keep the tree balanced and minimizes the number of disk accesses required. B-Trees are characterized by their order, which defines the maximum number of children each node can have. This structure ensures that the tree remains balanced, with all leaf nodes at the same depth, leading to improved performance for operations like searching and updating data.