Message-driven Beans (MDBs) are a type of enterprise bean in the Java EE (Enterprise Edition) framework that allows applications to process messages asynchronously. They are designed to handle messages from a Java Message Service (JMS) provider, enabling communication between different components of a distributed application without requiring them to be directly connected. MDBs automatically listen for incoming messages and can be triggered to execute business logic when a message arrives. This makes them ideal for scenarios where tasks need to be performed in response to events, such as processing orders or handling notifications, while maintaining scalability and reliability in enterprise applications.