I.O.I was a South Korean girl group formed by CJ E&M through the 2016 reality show Produce 101 on Mnet. The group was composed of eleven members chosen from various entertainment companies: Lim Na-young, Kim Chung-ha, Kim Se-jeong, Jung Chae-yeon, Zhou Jieqiong, Kim So-hye, Yoo Yeon-jung, Choi Yoo-jung, Kang Mi-na, Kim Do-yeon and Jeon So-mi. They debuted on May 4, 2016 with the EP Chrysalis and actively promoted as a whole and as a sub-unit for less than a year.

Stage Name: Nayoung/나영
Real Name: Lim Nayoung/임나영
Nicknames: Stone Nayoung
Birthday: December 18, 1995
Birthplace: Seoul, South Korea
Blood Type: O
Height: 171 cm
Weight: 50 kg
Position in group: Leader, Main Rapper, Lead Dancer, Vocalist
Original company: Pledis Entertainment
Languages: Korean
Hobbies: painting
Education: Dongduk Women’s University
Member of PRISTIN

Rank 10 on Produce 101

Stage Name: Chungha/청하
Real Name: Kim Chungha/김청하/Annie Kim
Birthname: Kim Chanmi/김찬미
Birthday: February 9, 1996
Birthplace: South Korea
Blood Type: B
Height: 161 cm
Weight: 44 kg
Position in Group: Main Dancer, Lead Vocalist, Rapper
Original company: M&H Entertainment
Languages: Korean, English
Hobbies: watching movies alone
Education: Sejong University

Rank 4 on Produce 101

Now a solo artist

Stage Name: Sejeong/세정
Real Name: Kim Sejeong/김세정
Nicknames: God Sejeong
Birthday: August 28, 1996
Birthplace: South Korea
Blood Type: AB
Height: 164 cm
Weight: 48 kg
Position in group: Main Vocalist
Original company: Jellyfish Entertainment
Languages: Korean
Hobbies: drawing, rewatching movies
Education: Indeogwon High School
Member of Gugudan

Rank 2 on Produce 101

Stage Name: Chaeyeon/채연
Real Name: Jung Chaeyeon/정채연
Birthday: December 1, 1997
Birthplace: Kyunggi, Seoul, South Korea
Blood Type: A
Height: 166 cm
Weight: 49 kg
Position in Group: Visual, Vocalist
Original company: MBK Entertainment
Languages: Korean
Education: Seoul School of Performing Arts
Member of DIA

Rank 7 on Produce 101

Stage Name: Pinky/핑키
Real Name: Zhou Jieqiong/周洁琼
Birthday: December 16, 1998
Birthplace: Shanghai, China
Blood Type: O
Height: 166 cm
Weight: 47 kg
Position in Group: Lead Dancer, Visual, Vocalist
Original company: Pledis Entertainment
Languages: Chinese, Korean
Instruments: pipa
Hobbies: shopping, searching beauty sites
Education: Shanghai Conservatory of Music; School of Performing Arts Seoul
Member of PRISTIN

Rank 6 on Produce 101

Stage Name: Sohye/소혜
Real Name: Kim Sohye/김소혜

Birthday: July 19, 1999
Birthplace: South Korea
Blood Type: A
Height: 163 cm
Weight: 48 kg
Position in Group: Vocalist, Rapper
Original company: Redline Entertainment
Languages: Korean
Instruments: ocarina
Hobbies: picking up trash
Fans: Penguins

Rank 5 on Produce 101

Stage Name: Yoojung/유정
Real Name: Choi Yoojung/최유정
Nicknames: Yoodaengi, Udon
Birthday: November 12, 1999
Birthplace: Guri, Gyeonggi, South Korea
Blood Type: O
Height: 159 cm
Weight: 44 kg
Position in Group: Lead Rapper, Lead Dancer, Lead Vocalist
Original company: Fantagio Entertainment
Languages: Korean
Hobbies: painting, photography, dancing
Siblings: none
Education: Seoul Music High School; Seoul School of Performing Arts
Member of Weki Meki

Rank 3 on Produce 101

Stage Name: Yeonjung/연정
Real Name: Yu Yeonjung/유연정
Birthday: August 3, 1999
Birthplace: Seoul, South Korea
Blood Type: A
Height: 167 cm
Weight: 52 kg
Position in Group: Main Vocalist
Original company: Starship Entertainment
Languages: Korean
Hobbies: playing alone
Siblings: one older brother
Member of WJSN/Cosmic Girls

Rank 11 on Produce 101

Stage Name: Doyeon/도연
Real Name: Kim Doyeon/김도연
Birthday: December 4, 1999
Birthplace: Wonju, Gangwon, South Korea
Blood Type: O
Height: 170 cm
Weight: 50 kg
Position in Group: Visual, Vocalist
Original company: Fantagio Entertainment
Languages: Korean
Hobbies: watching movies, listening to music
Siblings: older sister and older brother
Education: Sangji Girls High School; Seoul School of Performing Arts
Member of Weki Meki

Rank 8 on Produce 101

Stage Name: Mina/미나
Real Name: Kang Mina/강미나
Birthday: December 4, 1999
Birthplace: Jeju Island, South Korea
Blood Type: O
Height: 162 cm
Weight: 48 kg
Specialty: wacking
Position in Group: Lead Dancer, Vocalist, Rapper
Original company: Jellyfish Entertainment
Languages: Korean
Hobbies: watching plays and dramas, traveling alone
Education: Seoul School of Performing Arts
Member of Gugudan

Rank 9 on Produce 101

Stage Name: Somi/소미
Real Name: Jeon Somi/전소미/Ennik Somi Douma
Birthday: March 9, 2001
Birthplace: Canada
Blood Type: O
Height: 169 cm
Weight: 48 kg
Specialty: taekwondo, drawing caricatures, cooking
Position in group: Lead Dancer, Lead Vocalist, Rapper, Face of the Group, Maknae
Original company: -
Languages: English, Korean
Instruments: piano
Hobbies: collecting socks, looking for good songs, searching for restaurants
Siblings: one younger sister
Member of UNNIES (second generation) and Girls Next Door

Rank 1 on Produce 101