AutoIt is a freeware scripting language for automating tasks on Microsoft Windows using a BASIC-like syntax. It allows scripts to emulate keyboard and mouse input to control Windows applications. AutoIt can be used to automate common tasks like software installation, monitor websites and disks, and simulate user interactions for testing applications. While it has limitations like single-threading and difficulty debugging, AutoIt is commonly used for creating utility software, automating tasks, and developing game bots.