Girls' Generation-TTS is a sub-unit of Girls' Generation. The sub-unit consists of 3 members: Taeyeon, Tiffany and Seohyun. Tiffany and Seohyun have left SM Entertainment in 2018, they did not leave Girls' Generation. Because of this the future of the sub-unit is unclear.

Stage Name: Seohyun/서현
Real Name: Seo Joohyun/서주현/徐珠賢
Nicknames: Seororo
Birthday: June 28, 1991
Birthplace: Seoul, South Korea
Blood Type: A
Height: 168 cm
Weight: 49 kg
Position in group: Leader, Main Dancer, Lead Vocalist, Maknae
Languages: Korean, Chinese, Japanese
Instruments: piano, guitar
Hobbies: listening to music
Education: Daeyoung High School, Jeonju Art High School; Dongguk University
Fans: Seomate

Stage Name: Taeyeon/태연
Real Name: Kim Taeyeon/김태연/金泰妍
Nicknames: Kid Leader, Taengoo, Taeng, Byuntae, Tae Tae
Birthday: March 9, 1989
Birthplace: Jeonju, North Jeolla, South Korea
Blood Type: O
Height: 158 cm
Weight: 45 kg
Position in group: Main Vocalist, Lead Dancer, Lead Rapper, Visual, Center, Face of the Group
Languages: Korean, Japanese
Hobbies: watching movies, listening to music
Siblings: one older brother, one younger sister
Education: Jeonju Art High School
Fans: Taeganger

Stage Name: Tiffany/티파니
Real Name: Hwang Miyoung/황미영/黄美英/Stephanie Hwang
Nicknames: Fany, Mushroom, Manager Hwang, Ddilfany
Birthday: August 1, 1989
Birthplace: San Francisco, California, US
Blood Type: O
Height: 163 cm
Weight: 51 kg
Position in group: Main Rapper, Lead Vocalist
Languages: Korean, English, Chinese, Japanese
Instruments: flute
Hobbies: watching movies, listening to music, playing the flute
Siblings: one older sister, one older brother
Education: South Pointe Middle School; Diamond Bar High School; Korea Kent Foreign School
Fans: Fanytastic