电脑壁纸，又名电脑壁纸或桌面背景，是在桌面上可以随意个性化的图片，相类似的还有：鼠标指针与屏幕保护设备。电脑壁纸用于Microsoft Windows与Mac OS等操作系统。这词是描述一个重复去填满页面的图片。电脑屏幕是人和电脑对话的主要入口，也是人机交互的图形用户界面（人机接口），它主要分成：常用图标、系统菜单、任务栏以及背景图片。

随着电脑技术的发展，从黑白屏到彩屏，电脑的待机桌面不再由单一的颜色所组成，而是可以用一张图片来替换，这张壁纸便称之为电脑壁纸。电脑壁纸是电脑屏幕所使用的背景图片，可以根据大小和分辨率来做相应调整。电脑壁纸让我们的电脑看起来更好看、更漂亮和更有个性。

A wallpaper or background (also known as a desktop wallpaper, desktop background, desktop picture or desktop image on computers) is a digital image (photo, drawing etc.) used as a decorative background of a graphical user interface on the screen of a computer, mobile communications device or other electronic device. On a computer it is usually for the desktop, while on a mobile phone it is usually the background for the 'home' or 'idle' screen. Though most devices come with a default picture, users can usually change it to custom files of their choosing.