Girls' Generation (Korean: 소녀시대; RR: Sonyeo Sidae), also known as SNSD, is a South Korean girl group formed by SM Entertainment. The group is composed of eight members: Taeyeon, Sunny, Tiffany, Hyoyeon, Yuri, Sooyoung, Yoona, and Seohyun. Originally a nine-piece group, Jessica departed from the group in September 2014. One of the prominent figures of the Korean Wave, the group has won numerous accolades and the honorific nickname "The Nation's Girl Group".
Girls' Generation debuted in 2007 with their eponymous Korean debut album. The group rose to fame with the single "Gee" in 2009, which claimed the top spot on KBS's Music Bank for a record-breaking nine consecutive weeks and was named the most popular song of the 2000s in South Korea by Melon. Girls' Generation consolidated their popularity in South Korea with follow-up singles "Genie", "Oh!", and "Run Devil Run", which were released between mid-2009 and early 2010. Their second Korean studio album, Oh! (2010), won the Golden Disc award for Album of the Year, making the group the only female act to win the grand prize in the 2010s.
The group ventured into the Japanese music scene in 2011 with their eponymous Japanese debut album, which became the first album by a non-Japanese girl group to be certified million in Japan. The group's third Korean studio album, The Boys, was the best-selling album of 2011 in South Korea. An English version of the single "The Boys" was released in an attempt to expand the group's endeavor to the global music scene. The group's fourth Korean studio album, I Got a Boy (2013), was supported by the single "I Got a Boy", which won Video of the Year at the inaugural YouTube Music Awards. Girls' Generation released their fifth Korean studio album, Lion Heart in 2015, followed by Holiday Night in 2017.
The group's signature musical styles are characterized as electropop and bubblegum pop, though their sounds have varied widely, incorporating various genres including hip hop, R&B, and EDM. Girls' Generation are the first Asian girl group to achieve five music videos with over 100 million views on YouTube: "Gee", "I Got a Boy", "The Boys", "Mr. Taxi", and "Oh!". In Japan, they became the first non-Japanese girl group to have three number-one albums on the Japanese Oricon Albums Chart, and their three Japanese concert tours attracted a record-breaking 550,000 spectators.