Gugudan (also stylized as gugudan, gu9udan or gx9) is a South Korean girl group formed in 2016 by Jellyfish Entertainment.

They debuted, on June 28, 2016, with the mini-album, Act. 1 The Little Mermaid, and the title track “Wonderland”.

The group composed of eight members: Mimi, Hana, Haebin, Nayoung, Sejeong, Sally, Soyee and Mina. Originally a nine-piece group, Hyeyeon later departure from the group on October 25, 2018.

In July 2017, Jellyfish Entertainment formed the first subunit of Gugudan composed of two youngest members: Mina and Hyeyeon, named Gugudan 5959. The “5959” name is made up of their represented numbers in Gugudan: Hyeyeon representing the number 5 and Mina representing the number 9. 5959 released their debut single, “Ice Chu”, on August 10, 2017.

After Hyeyeon’s departure in October 2018, the subunit consequently became inactive.

In June 2018, Jellyfish Entertainment formed the second subunit of Gugudan composed of the three members: Sejeong, Mina and Nayoung named Gugudan SEMINA. The “SEMINA” name is made up of the first syllables of Sejeong, Mina and Nayoung. SEMINA debuted with the release of their self-titled single album consisting of two tracks on July 10, 2018.

After two years of inactivity as a group, Jellyfish Entertainment announced that Gugudan has disbanded on Dec. 31st, 2020.