Actor-based concurrency is a programming model that treats "actors" as the fundamental units of computation. Each actor can send and receive messages, maintain its own state, and create new actors. This model allows for parallel execution, as actors operate independently, making it easier to build scalable and responsive systems. In this model, actors communicate exclusively through asynchronous message passing, which helps avoid issues like shared state and locking. This approach is particularly useful in distributed systems, where actors can run on different machines, enhancing performance and reliability. Frameworks like Akka and Erlang utilize actor-based concurrency to simplify complex applications.