Who – quién
(Pronounced kyehn)
To remember that who is pronounced kyehn (quién) in Spanish, use the following mnemonic:
Who is the doctor putting the key in the engine (quién)?

Examples of quién (who) in a sentence
¿Quién es esa persona?
(Who is that person?)
No sé quién llamó anoche.
(I don't know who called last night.)
¿Quién quiere más café?
(Who wants more coffee?)