Coroutines are a programming construct that allows functions to pause and resume their execution. Unlike traditional functions that run from start to finish, coroutines can yield control back to the caller, enabling more efficient management of tasks, especially in asynchronous programming. This makes them useful for handling operations like I/O tasks without blocking the main program flow. In languages like Python and JavaScript, coroutines simplify the writing of concurrent code. They help developers create programs that can perform multiple tasks seemingly at the same time, improving responsiveness and performance in applications such as web servers and game engines.