CNBLUE (Korean: 씨엔블루) is a South Korean pop-rock band formed in 2009 under FNC Entertainment.

The band currently consists of three members: vocalist and guitarist Jung Yonghwa (정용화), rapper and bassist Lee Jungshin (이정신), and drummer Kang Minhyuk (강민혁).

The line-up initially consisted of the current members and bassist Kwon Kwangjin (권광진). He left the band following their debut Japanese EP Now or Never and was replaced by Lee Jonghyun (이종현), who was also a lead vocalist. Jonghyun left the band in August 2018.

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 Jonghyun, Minhyuk, Jungshin, and Yonghwa, respectively. On January 14, 2010, CNBLUE debuted with in Korea with the lead single “I’m a Loner” from their first Korean mini-album Bluetory and is considered as one of the best debuts in Korean music. Their fan club is named Boice, combining the words “blue” and “voice”.