While You Were Sleeping (Korean: 당신이 잠든 사이에; RR: Dangsini Jamdeun Saie) is a 2017 South Korean television series starring Lee Jong-suk, Bae Suzy, Lee Sang-yeob, and Jung Hae-in. Consisting of sixteen chapters distributed over 16 episodes, this legal drama-fantasy television series centers on the lives on three young adults—a field reporter, a prosecutor, and a police officer—who have acquired the ability to foresee future events through their dreams, after saving each other many years ago.

The series is directed by Oh Chung-hwan and written by Park Hye-ryun. It aired on SBS from September 27 to November 16, 2017 on Wednesdays and Thursdays at the 22:00 (KST) time slot. The drama completed filming and editing before airing the pilot episode. The drama is available on online streaming services such as Netflix, Viki, KOCOWA and Viu. iQIYI also broadcasts the drama.