Lee Hyo-ri (Korean: 이효리; born May 10, 1979) is a South Korean singer, record producer, activist, actress and television presenter. She debuted as a member of group Fin.K.L in 1998, which became one of the most popular girl groups in South Korea during the late 1990s and early 2000s. Aside from Fin.K.L, she has also participated in several project groups, including the Refund Sisters and SSAK3 in 2020.

Lee made her solo debut in August 2003 with the release of Stylish.... The album sold over 150,000 copies and spawned the hit single "10 Minutes". The song received widespread recognition in South Korea and led Lee to win numerous grand prizes (daesangs) at domestic year-end award ceremonies, including at the KBS Music Awards, SBS Gayo Daejeon, Mnet Music Video Festival, and the Seoul Music Awards. Her significant popularity in South Korea at the time was dubbed the "Hyori Syndrome" by Korean media, with some also deeming 2003 "the year of Hyori".

Lee's sophomore studio album, Dark Angel (2006), spawned several singles including "Get Ya!". The album was a critical failure, however, with "Get Ya!" receiving accusations of plagiarism. Her third studio album, It's Hyorish (2008), was better received critically and became the best-selling album by a female soloist in 2008. Its single, "U-Go-Girl", ranked atop the music program charts for multiple weeks. Lee once again faced plagiarism accusations with her next album, H-Logic (2010), when composer Bahnus was found to have plagiarized seven of the album's tracks. She subsequently took a temporarily hiatus from the entertainment industry, and became a spokesperson for various causes such as animal rights.

On television, Lee was dubbed the "Nation's Fairy" during her days on variety show Family Outing, and received the Grand Prize at the 2009 SBS Entertainment Awards for the program (alongside Yoo Jae-suk). In 2006, Lee became the highest-paid female singer in South Korea when she signed a contract with Mnet Media. The Korea Times named Lee one of the top 10 Most Influential Women on the Cultural Scene since 1950. Mnet ranked her number 42 in their Legend 100 Artists list in 2013.