Doh Kyung-soo (도경수; born January 12, 1993), known professionally as D.O. (디오), is a South Korean singer and actor under SM Entertainment. He is a member of the South Korean boy group EXO and its sub-group EXO-K.

Apart from his group's activities, D.O. has starred in various television dramas and movies such as Pure Love (2016), My Annoying Brother (2016), Positive Physique (2016), Room No.7 (2017), 100 Days My Prince (2018), Along with the Gods: The Two Worlds, Swing Kids (2018) and Bad Prosecutor (2022).

He made his solo debut on July 26, 2021 with his first mini album Empathy.