琴键（Keyboard）是键盘乐器和部份有音高的敲击乐器的重要部件，当中键盘乐器多采用活动式的设备，按压后琴键会返回原来位置，例如钢琴、数字钢琴、电子琴、管风琴、大键琴等，也适用于敲击乐器中的钢片琴；至于如木琴、马林巴、颤音琴等敲击乐器，则纯綷指不同音高的发声体按键盘乐器的排列方式放置，但仍可统称为「琴键」。

有些民族乐器亦可采用类似按钮设备的「琴键」，间接协助制造出声音，如日本的大正琴、印度的西塔琴等。另外，魔音琴（合成器的一种）是运用电子的方法合成出声音的机器。

出产键盘乐器中的琴键厂牌有很多，比较知名的就是YAMAHA、Roland和KORG。

A musical keyboard is the set of adjacent depressible levers or keys on a musical instrument. Keyboards typically contain keys for playing the twelve notes of the Western musical scale, with a combination of larger, longer keys and smaller, shorter keys that repeats at the interval of an octave. Depressing a key on the keyboard makes the instrument produce sounds, either by making a hammer mechanically strike a string or tine (piano, electric piano, clavichord); pluck a string (harpsichord); open a valve to let air flow through a pipe (pipe organ or accordion); or strike a bell (carillon in a church tower). On electric and electronic keyboards, depressing a key connects one or more circuits (Hammond organ, digital piano, synthesizer, MIDI controller keyboard), which triggers a sound. A pedal keyboard is a keyboard played with the feet, usually used with a pipe organ or theatre organ. Since the most commonly encountered keyboard instrument is the piano, the keyboard layout is often referred to as the "piano keyboard".