图形用户界面（Graphical User Interface，简称GUI）是指采用图形方式显示的计算机操作用户接口。与早期计算机使用的命令行界面相比，图形界面对于用户来说在视觉上更易于接受。然而这接口若要透过在显示器的特定位置，以「各种美观、而不单调的视觉消息」提示用户「状态的改变」，势必得比简单的文本消息呈现，花上更多的电脑运算能力，计算「要改变显示器哪些光点，变成哪些颜色」。

In computer science, a graphical user interface or GUI, pronounced /ˈɡuːi/ ("gooey") is a type of interface that allows users to interact with electronic devices through graphical icons and visual indicators such as secondary notation, as opposed to text-based interfaces, typed command labels or text navigation. GUIs were introduced in reaction to the perceived steep learning curve of command-line interfaces (CLIs), which require commands to be typed on the keyboard.