声卡是多媒体电脑中用来处理声音的接口卡。声卡可以把来自话筒、收音机、录音机、激光唱机（激光影碟）等设备的语音、音乐等声音变成数字信号交给电脑处理，并以文档形式存盘，还可以把数字信号还原成为真实的声音输出。声卡尾部的接口从机箱后侧伸出，上面有连接麦克风、音箱、游戏杆和MIDI设备的接口。

但自从各大主板厂商推广All-In-One的主板以来，主板皆内置AC97或新款HD Audio，迫使中低级的声卡市场快速萎缩，仅剩高端与专业用途声卡仍存在于市场。

A sound card (also known as an audio card) is an internal computer expansion card that facilitates economical input and output of audio signals to and from a computer under control of computer programs. The term sound card is also applied to external audio interfaces that use software to generate sound, as opposed to using hardware inside the PC. Typical uses of sound cards include providing the audio component for multimedia applications such as music composition, editing video or audio, presentation, education and entertainment (games) and video projection.