The group had eight members: Mimi, Hana, Haebin, Nayoung, Sejeong, Sally, Soyee and Mina. note Three members - Nayoung, Sejeong, and Mina - participated in the first season of Produce101. Because they were in the final 11, Sejeong and Mina debuted in I.O.I.
gu9udan debuted on June 28, 2016 with the single 'Wonderland' and the mini-album 'Act. 1 The Little Mermaid'.
Their first subunit 'gugudan 5959' or 'gugudan Ogu-ogu' - which consisted of their two youngest members - debuted August 10, 2017 with the single 'Ice Chu'.
Another subunit 'SEMINA' - Sejeong, Nayoung, Mina - debuted July 10, 2018 with 'SAEMINA', the subunit name being made up of the first syllables of their names.
The group went on hiatus in 2018, and following two years of inactivity, announced their disbandment in 2020. Fans were saddened but not surprised, as Sally (while appearing on a Chinese survival show) had revealed that the girls had essentially been evicted from their dorms and told to not come back unless they were specifically requested to. She also mentioned that there had been a rather large popularity gap between two of the membersnote , which many suspect lead to the group not succeeding (it's important to note, however, that all the girls seem to be on good terms with each other despite this).
- Mimi (Jung Mimi, born January 1, 1993)
- Hana (Shin Bora, born April 30, 1993)
- Haebin (Han Haebin, born August 16, 1995)
- Nayoung (Kim Nayoung, born Novemver 23, 1995)
- Sejeong (Kim Sejeong, born August 28, 1996)
- Sally (Liu Xie Ning/Ryu Sajeonote , born October 23, 1996)
- Soyee (Jang Sojin, born November 21, 1996)
- Mina (Kang Mina, born December 4, 1999)
- Hyeyeon (Cho Hyeyeon, born August 5, 2000)note
Members in gugudan 5959:
Members in guguda SEMINA:
- Act. 1 The Little Mermaid - Jun. 28, 2016
- Act. 2 Narcissus - Feb. 27, 2017
- Act. 3 Chococo Factory - Nov. 8, 2017
- Act. 4 Cait Sith - Feb. 1, 2018
- Act. 5 New Action - Nov. 6, 2018
Tropes Related to gu9udan:
- Absentee Actor: Well, singer. Soyee wasn't present for Act. 3 and Hyeyeon left the group after Act. 4.
- Aerith and Bob: Mimi, Hana, Haebin, Nayoung, Sejeong, Soyee, Mina, Hyeyeon and Sally.
- all lowercase letters: How 'gugudan' is usually written.
- Blonde, Brunette, Redhead: SEMINA has this with Nayoung, Sejeong and Mina respectively. In the main group, Nayoung is frequently blonde, Mina's hair has been consistently red since their debut and Haebin is usually redheaded while Sally's had blonde and red hair. Soyee's previously dyed hers with a red dark enough to be almost brown. Oddly, Sejeong and Mimi have stayed brunette but have lightened it significantly. Hana's the only exception thus far.
- Chronological Album Title: Act. 1 The Little Mermaid, Act. 2 Narcissus, Act. 3 Chococo Factory, Act. 4 Cait Sith, Act. 5 New Action.
- Fan Community Nickname: Dan-jjakn (Dear Friend).
- Girl Group: A Korean Pop Music example.
- The Leader: Hana.
- Letters 2 Numbers: '9' to replace a 'g' in 'gu9udan'.
- Just for Pun:
- The music video for "A Girl Like Me" features them doing multiplication on a chalkboard and a whiteboard and interviewers frequently quiz the girls on it. This is because the characters for gugudan directly translate to "multiplication table" in English.
- SEMINA's premiere song is Saemina, which is pronounced the exact same way as the subunit's name.
- Non-Uniform Uniform: Their stage outfits for Act. 1 through Act. 4. Act. 5 has a much looser approach but there's still hints of this.
- One-Word Title:
- 'Diary' and 'Wonderland' in Act. 1 The Little Mermaid.
- 'Rainbow' in Act. 2 Narcissus.
- 'Chococo', 'Lucky', and 'Snowball' in Act. 3 Chococo Factory.
- 'Silly' and 'Lovesick' in Act. 4 Cait Sith.
- 'Dear' and 'Shotgun' in Act. 5 New Action.
- Stage Names:
- Hana for Bo Ra
- Sally for Xiu Ning/Sa Jeo
- Soyee for So Jin
- Team Mom: Haebin is said to be the "mother of the group".
- Token Minority: Sally, who's Chinese, is the only non-Korean member of the group.