后台进程（Background Process）是一种在不需用户干预的情况下运行于操作系统后台的计算机进程 ，通常用于执行如日志记录、系统监测、作业调度以及用户提醒等任务。

在UNIX与类UNIX系统中，后台进程的进程组ID（即PGID，可用ps命令获得）与控制终端进程组ID（即TPGID）不同，因而也可以此辨识后台进程。后台进程无法接收从键盘传送的信号（如Ctrl-C），但从更专业的定义来说，进程是否能收到用户的中断信号并非后台进程的判别标准。

虽然后台进程通常用于仅需少量资源的应用，但任何进程无论占用资源多少都可以运行在后台，且即使进程在后台运行，其行为与前台进程也并无差异。

A background process is a computer process that runs "behind the scenes" (i.e. in the background) and without user intervention. Typical tasks for these processes include logging, system monitoring, scheduling, and user notification.

On a Windows system, this term may be used to either refer to a computer program that does not create a user interface, or a Windows service. The former are started just as any other program is started, e.g. via Start menu. Windows services, on the other hand, are started by Service Control Manager. In Windows Vista and later, they are run in a separate session. There is no limit on how much a system service or background process can use system resources. Indeed, in Windows Server family of Microsoft operating systems, background processes are expected to be the principle consumers.