Wonder Girls (Korean: 원더걸스) was a South Korean girl group formed by JYP Entertainment. The group debuted in February 2007 with the single "Irony" and 5 members: Yeeun, Sunye, Sunmi, Hyuna, and Sohee. After Hyuna's departure in July, Yubin was added into the group prior to the release of their debut studio album, The Wonder Years (2007). The album spawned the hit single "Tell Me", which topped various South Korean music charts.

Wonder Girls further established themselves as one of the top girl groups in the country with the hit singles "So Hot" and "Nobody", released in 2008. After being released as a single in the U.S. in 2009, "Nobody" charted at No. 76 on the Billboard Hot 100, making Wonder Girls the first South Korean act to enter the chart. The group began their entry into the American market the same year as an opening act for the Jonas Brothers' World Tour, performing English versions of their songs.

In early 2010, Sunmi left the group to pursue an academic career and was replaced by Hyerim prior to the worldwide release of the single "2 Different Tears" later that year. Their second studio album, Wonder World (2011), yielded the hit single "Be My Baby". In 2012, Wonder Girls starred in the TeenNick movie The Wonder Girls, and released their last 3 singles as a quintet, notably "Like This" and "Like Money", before going on a 3-year long hiatus. In 2015, it was announced that Sunye and Sohee decided to leave the group while Sunmi would resume promotion with the remaining members. The 4-piece adapted a band-oriented concept for their acclaimed third and final studio album, Reboot (2015), and the No. 1 2016 single "Why So Lonely".

Wonder Girls are also known as "South Korea's Retro Queens", as their music has been noted to contain elements from the 1960s through 80s. In 2017, Billboard ranked Wonder Girls at number 3 on their "Top 10 K-pop Girl Groups of the Past Decade" list. The group officially disbanded on January 26, 2017, after unsuccessful contract renewal negotiation with some of its members. On February 10, 2017, they released their final single "Draw Me", which also served as a celebration of their 10th anniversary.