What Is Love? is the fifth extended play by South Korean girl group Twice. It was released on April 9, 2018, by JYP Entertainment and is distributed by Iriver. It includes the title track of the same name produced by Park Jin-young. Twice members Jeongyeon, Chaeyoung, and Jihyo also took part in writing lyrics for two songs on the EP.

Twice is a South Korean girl group formed by JYP Entertainment. The group is composed of nine members: Nayeon, Jeongyeon, Momo, Sana, Jihyo, Mina, Dahyun, Chaeyoung, and Tzuyu. Twice was formed under the television program Sixteen (2015) and debuted on October 20, 2015, with the extended play (EP) The Story Begins, and has received the honorific title of "The Nation's Girl Group" in their home country.