页缺失（英语：Page fault，又名硬错误、分页错误、寻页缺失、缺页中断、页故障等）指的是当软件试图访问已映射在虚拟地址空间中，但是目前并未被加载在物理内存中的一个分页时，由中央处理器的内存管理单元所发出的中断。

通常情况下，用于处理此中断的进程是操作系统的一部分。如果操作系统判断此次访问是有效的，那幺操作系统会尝试将相关的分页从硬盘上的虚拟内存文档中调入内存。而如果访问是不被允许的，那幺操作系统通常会结束相关的进程。

虽然其名为“页缺失”错误，但实际上这并不一定是一种错误。而且这一机制对于利用虚拟内存来增加进程可用内存空间的操作系统（比如Microsoft Windows和各种类Unix系统）中都是常见且有必要的。

A page fault (sometimes called #PF, PF or hard fault) is a type of interrupt, called trap, raised by computer hardware when a running program accesses a memory page that is mapped into the virtual address space, but not actually loaded into main memory. The hardware that detects a page fault is the processor's memory management unit (MMU), while the exception handling software that handles page faults is generally a part of the operating system kernel. When handling a page fault, the operating system generally tries to make the required page accessible at the location in physical memory, or terminates the program in case of an illegal memory access.