Kim Hyun-ah (Korean: 김현아; born June 6, 1992), known professionally as Hyuna (stylized as HyunA), is a South Korean singer-songwriter, rapper and model. She debuted as a member of the girl group Wonder Girls in February 2007. Upon leaving the ensemble shortly after, Hyuna subsequently left JYP Entertainment and joined the girl group 4Minute. The group debuted in June 2009 under Cube Entertainment. In 2010, Hyuna began a solo career with a style she described as "performance-oriented music". Her solo debut single "Change" charted at number-two on South Korea's Gaon Digital Chart.

In 2011, Hyuna gained wider public recognition with the release of her first extended play Bubble Pop!. The title track sold more than three million digital copies and she became the first female K-pop solo artist to reach 100 million views on a single music video on YouTube. Later the same year, she formed the duo Trouble Maker with former Beast member Hyunseung, releasing the hit single "Trouble Maker". In 2012, she appeared in a successful duet rendition of Psy's worldwide hit "Gangnam Style" and later released her second extended play Melting, which featured the number-one single "Ice Cream". Her next two extended plays A Talk and A+ yielded the successful singles "Red" and "Roll Deep", respectively. Following 4Minute's disbandment in mid-2016, she released her fifth extended play A'wesome, which was supported by her first concert tour The Queen's Back. In 2017, she was involved in the trio Triple H with Pentagon members Hui and E'Dawn before releasing her sixth extended play Following.

In 2018, Hyuna ended her contract with Cube Entertainment after several internal conflicts, and signed with Psy's P Nation the following year. Her first digital single under P Nation "Flower Shower" became her seventh top-ten entry on the US Billboard World Digital Song Sales. In 2021, Hyuna released her seventh extended play I'm Not Cool.

Hyuna was born on June 6, 1992 in Seodaemun District, Seoul, South Korea. She attended Choongam Middle School and Korea High School of Music and Arts. Hyuna graduated from Konkuk University, in Contemporary Arts, and received special admission into the school.

In 2006, she was revealed as a member of the JYP Entertainment managed girl group Wonder Girls as the group's main rapper. Hyuna participated in the group's debut mini album The Wonder Begins, released in February 2007. She participated in the group's television show MTV Wonder Girls for two seasons, and co-hosted Show! Music Core with Wonder Girls' Sohee and Fly to the Sky singer Brian Joo from May 12 – June 30, 2007. Hyuna left Wonder Girls in July, when she was removed by her parents due to their concern over her health, particularly chronic gastroenteritis and fainting spells. In 2008, she joined Cube Entertainment. In May 2009, it was announced that Hyuna would debut as part of the girl group 4Minute. The group debuted with the single "Hot Issue" on June 15.

Hyuna collaborated with Lee Gi-kwang on the song "2009" for his debut album First Episode: A New Hero, and also appeared in the music video of his single "Dancing Shoes," which was released on March 30, 2009. On August 13, she rapped for Navi's song "Wasteful Tears" and she also appeared in the music video. Hyuna also featured in Brave Brothers' song "Bittersweet," released August 18. She became part of the "Dream Team Girl Group," a promotional group for Samsung's Anycall phone with Han Seung-yeon, Uee, and Gain. Their first digital single "Tomorrow" was released on October 6, 2009, and the official music video was released on October 12, starring actor Lee Dong-gun. As well, Hyuna released an individual version of the music video which released on October 27. She also participated in the South Korean variety show Invincible Youth. However, Hyuna left the show due to some scheduling conflicts with her group's overseas promotions on June 11, 2010.

On January 4, 2010, she released the single "Change", which charted highly on various online charts. The song reached number fourteen on the Gaon 2010 digital yearly chart with 2,469,354 copies sold. Ten days later, on January 14, the "Change" music video was flagged with a 19+ rating by the Ministry of Gender Equality and Family for being inappropriate for minors. Cube Entertainment stated that the music video would be re-edited and submitted for approval. However, broadcast station SBS, announced the music video would be restricted for a 15+ audience instead, and MBC announced that it would still be viewable for all audiences. Hyuna's "Change" promotions ended in March 2010. She released a few more singles in 2010, including "Love Parade" featuring T-max's member Park Yun-hwa, "Outlaw in the Wild" featuring Nassun, and produced by E-Tribe. Hyuna also participated in G.NA's duet single "Say You Love Me", for which she wrote the rap lyrics. In October 2010, she made a cameo appearance in the thriller film Midnight FM with 4Minute member Jihyun on October 14, 2010.

In 2011, Hyuna appeared in the Korean version of Dancing with the Stars. The show began broadcasting on June 10. The same year, she released her first mini album, Bubble Pop, featuring five new songs including the title track of the same name. The single was a global success, and featured on top of YouTube's "most watched today" chart after gaining one million views in two days. It eventually became the first music video by a K-pop artist to surpass 100 million views. Hyuna was ranked 17th on Billboard's '21 Under 21′, a staff-compiled list of notable young acts; while "Bubble Pop" was listed as ninth place on Spin magazine's "Best 20 Songs of 2011." On November 24, 2011, Cube revealed that she would be in a co-ed unit called Trouble Maker with BEAST's Hyunseung. Trouble Maker's first mini album, Trouble Maker, consisted of a dance track and an emotional ballad, as well as solo songs for both Hyuna and Hyunseung. Trouble Maker performed for the first time at the Mnet Asian Music Awards.