Mary Stayed Out All Night is a 2010 South Korean romantic comedy television series, starring Moon Geun-young, Jang Keun-suk, Kim Jae-wook and Kim Hyo-jin. It is based on the webcomic of the same title by Won Su-yeon. It aired on Korean Broadcasting System from November 8, to December 28, 2010 on Mondays and Tuesdays at 21:55 for 16 episodes.