Asynchronous I/O is a method of input/output processing that allows a program to continue executing while waiting for data to be read or written. Instead of blocking the program's execution until the operation completes, it sends a request and moves on to other tasks. This improves efficiency, especially in applications that handle multiple operations simultaneously. In computer programming, asynchronous I/O is commonly used in network communications and file handling. It enables better resource utilization and responsiveness, as the program can perform other computations or handle user interactions while waiting for I/O operations to finish.