Rainbow ( 레인보우) is a 7-member South Korean girl group under DSP Entertainment; The Member Include; Kim Jaekyung, Oh Seunga, No Eul ,Jung Yoonhye, Kim Jisook , Cho Hyunyoung and Go Woori – Each of the Seven girls representing a different colour of the ‘rainbow’.
Rainbow has been trained under DSP Media before KARA was formed.Around January 2009, rumors arose about DSP’s new girl group, Rainbow, but it was not confirmed until the group was finally revealed on November 3, 2009. It was rumored to be composed of seven girls, one for each color of the rainbow. DSP Media reportedly trained some members of the new band for four years. In late October and early November DSP Entertainment teased a new picture of Rainbow each day and then released a music video teaser for “Gossip Girl” on November 6, 2009.
On November 11, 2009, the music video for “Gossip Girl” was released. On November 12, 2009, the mini album was released which includes 5 songs. On November 14, 2009, they debuted on Music Core with the group’s first single “Gossip Girl”. 
After the promotion of “Gossip Girl”, the girls began the promotion of “Not Your Girl”, which was a response to SS501’s song “UR Man”.
In early August 2010, Rainbow released a new digital single called “A”. Recently, the company unleashed the new album jacket photo online, and the concept that opposes to the rainbow colours has become a hot topic.
On the October 19, 2010, DSP unleashed the groups’ concept photos for their new single – “Mach”, the girls have transformed into sexy dominatrix image for the comeback. The group made their comeback on the 21st of October 2010 through Mnet M! Countdown.
In April 2011, the girls released their second mini album “So Girls”. The title track, titled “To Me”, was released to promote the album, and has been charting high on many online music charts.