优先权倒置，又称优先权反转、优先权逆转、优先权翻转，是一种不希望发生的任务调度状态。在该种状态下，一个高优先级任务间接被一个低优先级任务所抢先(preemtped)，使得两个任务的相对优先级被倒置。

这往往出现在一个高优先级任务等待访问一个被低优先级任务正在使用的临界资源，从而阻塞了高优先级任务；同时，该低优先级任务被一个次高优先级的任务所抢先，从而无法及时地释放该临界资源。这种情况下，该次高优先级任务获得执行权。

在多数个案，发生优先权倒置并不导致直接伤害──高优先权任务的延迟运行不被察觉，最终，低优先权任务释放共享资源。虽然，亦存在很多情况优先权倒置会导致严重问题

In computer science, priority inversion is a problematic scenario in **** in which a high priority task is indirectly preempted by a medium priority task effectively "inverting" the relative priorities of the two tasks.

This violates the priority model that high priority tasks can only be prevented from running by higher priority tasks and briefly by low priority tasks which will quickly complete their use of a resource shared by the high and low priority tasks.