Super Junior (Korean: 슈퍼주니어), also known as simply SJ or SuJu (Korean: 슈주), is a thirteen-member Korean boy band formed by SM Entertainment in 2005, masterminded by Lee Soo Man. The group initially debuted with twelve members on November 6, 2005 with the single, "TWINS (Knock Out)". The original twelve members, from oldest to youngest, are Leeteuk (the leader), Heechul, Han Geng, Yesung, Kangin, Shindong, Sungmin, Eunhyuk, Donghae, Siwon, Ryeowook, and Kibum. The Chinese member, Han Geng, was chosen among the 3,000 applicants through auditions held in China by SM Entertainment in 2001.

Many of the members had already pursued an entertainment career before Super Junior's debut through acting, DJ-ing, and modeling. On May 23, 2006 SM Entertainment announced the addition of a new member, Kyuhyun, making them the thirteen-member group they are today. Moreover, before the addition of their 13th member, they were simply a project group named SuperJunior05. With his addition, the "05" was dropped and Super Junior became an official band.

Super Junior also has four sub-units with three different concentrations. The first sub-unit debuted November 5, 2006 with "한 사람만을 (The One I Love)" on KBS Music Bank. The sub-group is made out of Kyuhyun, Ryeowook, and Yesung, titling the group Super Junior-K.R.Y. by taking the first letter of each participating member's first name. They concentrate mainly on ballads since each member has a very strong, distinct and incredible voice. Their releases have all been on OSTs and SMTown releases.

On February 25, 2007, the next sub-unit Super Junior-T with "로꾸거!!!" on SBS Inkigayo. The T in the name stands for their concentration on the Trot genre, aiming at the older generation of Korea. The members include Leeteuk, Heechul, Kangin, Shindong, Sungmin, and Eunhyuk. They've released on single, "로꾸거!!!", which included a duet with Bang Silee.

After Super Junior-T came out with their single, it was said they were to soon release another mini-album. However, the third subgroup Super Junior-Happy formed instead. Super Junior-Happy made an unofficial debut performance on May 3, 2008 at the Power Concert although they had not formally introduced themselves as the subgroup at the time. Super Junior-Happy consists of every previous member of Super Junior-T except for Heechul, who was replaced by Yesung. On May 30, 2008, SM Entertainment released the official announcement of the subgroup through Newsen. The subgroup's first mini album with the title track, "Cooking? Cooking!" was released on June 5, 2008.

Very recently, on April 8, 2008, the sub-unit Super Junior-M was announced with the members Hangeng, Siwon, Donghae, Ryeowook, and Kyuhyun, plus two SM Trainees Zhoumi and Henry. The M in the name stands from Mandarin, the language of their releases since their concentration is entirely on China and Chinese speaking countries. Currently, they are promoting their album 謎 (Me) which has been released May 2008.