asyncio is a Python library used for writing concurrent code using the async/await syntax. It allows developers to run multiple tasks at the same time without blocking the main program, making it ideal for I/O-bound operations like web requests or file handling. With asyncio, you can create coroutines, which are special functions that can pause and resume their execution. This enables efficient management of tasks, as the program can switch between them while waiting for external resources, improving performance and responsiveness in applications.