A priority queue is a special type of data structure that stores elements with associated priorities. In a priority queue, elements are processed based on their priority rather than their order in the queue. This means that the element with the highest priority is removed first, regardless of when it was added. Priority queues are commonly implemented using data structures like heaps or binary trees. They are useful in various applications, such as scheduling tasks in operating systems or managing events in simulations, where certain tasks need to be prioritized over others.