Twice (Hangul: 트와이스; Japanese: トゥワイス; stylized as TWICE) is a South Korean girl group formed by JYP Entertainment through the 2015 reality show Sixteen. The group is composed of nine members: Nayeon, Jeongyeon, Momo, Sana, Jihyo, Mina, Dahyun, Chaeyoung, and Tzuyu. The group debuted on October 20, 2015 with the extended play (EP) The Story Begins.

Twice rose to fame in 2016 with their song "Cheer Up" charted number 1 on Gaon Digital Chart and became the best-performing single that year. It also won Song of the Year in two major music awards shows, Melon Music Awards and Mnet Asian Music Awards. Another song of the group, "TT" from their third EP Twicecoaster: Lane 1, claimed the top spot for four consecutive weeks. The EP was the highest selling K-pop girl group album of 2016, which sold 350,852 copies at year-end. Within 19 months after debut, Twice has sold over 1.2 million units of their four EPs and special album.

The group officially debuted in Japan on June 28, 2017 under Warner Music Japan with the release of their first compilation album titled #Twice. The album debuted at number 2 on Oricon Albums Chart, which sold 136,157 copies within seven days, the highest first week album sales among K-pop artists in Japan in the last two years.