Hyoyeon (효연), also known as DJ HYO and HYO, is a South Korean singer under SM Entertainment. She is a member of the Korean pop girl group Girls' Generation.
- Stage Names: Hyoyeon (효연), DJ HYO, HYO
- Birth Name: Kim Hyoyeon (김효연)
- Nicknames: Princess Fiona, Dancing Queen
- Birthdate: September 22, 1989
- Birthplace: Incheon, South Korea
- Blood Type: AB
- Height: 160cm
- Weight: 49kg
- Religion: Christian
- Languages: Chinese (Fluent), Japanese (Basic), English (Basic)
- Education: Chungbuk Middle School
- Hobbies: Shopping, Movies
- Relationship: Kim Joon Hyung (Writer) (2012–2014)
Kim is most known for her popping, waving, and Hip-hop dancing techniques that she learned from the Winners Dance School while she was a trainee. Prior to her debut, she traveled to Beijing, China in 2004 with Super Junior’s Siwon to learn Mandarin and more about Chinese culture.
- She was a trainee with SM Entertainment for six years and one month.
- She was BoA's silhouette dancer in her "Over the Top" performance at the 2005 M.net Asian Music Awards.
- She became an SM Entertainment trainee when she was twelve years old in 2000 by being discovered at an SM Entertainment casting system.
- She learned Jazz dance, Latin dance, and a variety of other styles when she was in elementary school. She didn't become interested in Hip-hop dance until she entered junior high school.