- Korean Name: Seo Eun Kwang (서 은광)
- Stage Name: Eunkwang (은광)
- Birthday: November 22, 1990
- Position: Leader, Main Vocalist
- Nationality: Korean
- Height: 173cm (5'6")
- Weight: 62kg
- Specialties: Piano
- Subunits: BTOB Blue, BTOB 4U
- Korean Name: Lee Mink Hyuk (이 민혁)
- Stage Name: Minhyuk (민혁)
- Birthday: November 29, 1990
- Position: Vocalist, Main Rapper, Face of the Group
- Nationality: Korean
- Height: 173cm (5'6")
- Weight: 61kg
- Specialties: Composing, Exercising, Acrobatics
- Subunits: BTOB 4U
- Korean Name: Lee Chang Seob (이창섭)
- Stage Name: Changsub (창섭)
- Birthday: February 26, 1991
- Position: Lead Vocalist
- Nationality: Korean
- Height: 177cm (5'8")
- Weight: 64kg
- Specialties: Piano, Drums
- Subunits: BTOB Blue, BTOB 4U
- Korean Name: Lim Hyun Sik (임 현식)
- Stage Name: Hyunsik (현식)
- Birthday: March 7, 1992
- Position: Vocalist, Dancer
- Nationality: Korean
- Height: 177cm (5'8")
- Weight: 66kg
- Specialties: Composer, Guitar, Piano
- Subunits: BTOB Blue
- Korean Name: Shin Dong Geun (신동근)
- Stage Name: Peniel (페니엘)
- Birthday: March 10, 1993
- Position: Vocalist, Dancer, Rapper
- Nationality: Korean
- Height: 175cm (5'7")
- Weight: 63kg
- Specialties: Guitar, Acting, Fluent in English
- Subunits: BTOB 4U
- Korean Name: Yook Sung Jae (육성재)
- Stage Name: Sungjae (성재)
- Birthday: May 2, 1995
- Position: Vocalist, Rapper, Maknae
- Nationality: Korean
- Height: 180cm (5'9")
- Weight: 68kg
- Specialties: Acting, Snowboarding, Fishing
- Subunits: BTOB Blue
Former Members
- Korean Name: Jung il Hoon (정일훈)
- Stage Name: Ilhoon (일훈)
- Birthday: October 4, 1994
- Position: Vocalist, Dancer, Rapper
- Nationality: Korean
- Height: 176cm (5'7")
- Weight: 64kg
- Specialties: Composer