CNBLUE (Korean: 씨엔블루) is a South Korean pop rock band formed in 2009. The band consists of Jung Yong-hwa (leader, main vocals, guitar, keyboard, rap), Kang Min-hyuk (drums), and Lee Jung-shin (bass). First bassist Kwon Kwang-jin left the band after they released their debut Japanese extended play Now or Never in 2009, and was replaced by Lee Jung-shin. Lee Jong-hyun (guitar and vocals) left the band on August 28, 2019.

CN is an initialism for Code Name, while BLUE is a backronym for burning, lovely, untouchable, and emotional; it is meant to portray the images of Jong-hyun, Min-hyuk, Jung-shin, and Yong-hwa, respectively. On January 14, 2010, CNBLUE debuted in Korea with the lead single "I'm a Loner" from their first Korean EP Bluetory.