Output iterators are a type of iterator in programming that allows you to write or output data to a destination, such as a container or a file. They provide a way to sequentially insert elements into a data structure, enabling efficient data manipulation. Output iterators typically support operations like assignment and incrementing, which facilitate the addition of new elements. These iterators are commonly used in conjunction with algorithms from the Standard Template Library (STL) in languages like C++. They help streamline processes like filling a vector or writing data to a stream, making it easier to manage collections of data.