After School (Korean: 애프터스쿨) was a South Korean girl group formed by Pledis Entertainment, with an admissions and graduation concept.

After School officially debuted in January 2009 with the song "AH!" from the single album New Schoolgirl. Following the addition of Uee in April of that year, they released "Diva", which won the "Rookie of the Month" award at the Cyworld Digital Music Awards. Pledis Entertainment then announced the graduation of Soyoung before adding Raina and Nana for the release of "Because of You", which topped the monthly digital chart for December 2009. Follow-up singles "Bang!", "Shampoo", "Flashback" and "First Love" further consolidated their popularity and saw the additions of members Lizzy, E-Young and Kaeun, as well as the graduations of original members Bekah and Kahi. In 2010, the three newest members at that time formed the group's first subunit, Orange Caramel, and in 2011 a second subunit was formed when the group was split into two teams, A.S. Red and A.S. Blue, for the release of their fourth single album.

In the beginning of 2011, the group signed with Avex Trax to begin their promotions in Japan. The group made their first official appearance in Japan by collaborating with singer Namie Amuro for a song from her collaboration album Checkmate!, titled "Make it Happen". The song won Best Collaboration at the 2012 MTV Video Music Awards Japan. The group's debut single, a remake of their Korean hit "Bang!", was released in August that year and charted at number seven on the Oricon Singles Chart. Their debut Japanese album, Playgirlz, was released in 2012 and their second Japanese album, Dress to Kill, fronted by the Shinichi Osawa produced singles "Heaven" and "Shh", was released in 2014.

After School received attention for their unique live performances, often incorporating different performance styles into their songs, including drums, tap dancing and pole dancing. The group received the Minister of Culture, Sports and Tourism Commendation in 2011 and was ranked number five in Billboard's 2017 list of the Top 10 K-pop Girl Groups of the Past Decade. From 2015 onward, Pledis halted both After School and Orange Caramel promotions and the members have embarked on individual music, acting and modeling careers. In 2019, Lizzy revealed that all members had gradually gone their separate ways.