S.O.A.P. is a Danish pop duo consisting of sisters Heidi and Line Sørensen that released two albums between 1998 and 2000 and sold around two million records. Their biggest hit was their debut single This Is How We Party, which made pop charts around the world, including the Billboard Hot 100 in the U.S.

S.O.A.P. is also the abbreviation of the Japanese rock band SONS OF ALL PUSSYS.

Heidi and Line (or Saseline) Sørensen were born in 1979 and 1982, respectively, both in Malaysia. Their mother is Malay and their father Danish, and they lived in both countries during their childhoods. They began singing and performing early in life, encouraged by their parents. After they met Danish songwriter‑producer Remee in 1995, they were signed to Sony Music as S.O.A.P. (pronounced as "soap").

Their first album, Not Like Other Girls, was first released in spring of 1998, along with first single This Is How We Party. Internationally, the group was managed by Simon Fuller, and the group became an international hit with chart positions in Europe, Japan, Australia and the U.S. alike. The girls also toured with The Backstreet Boys and won two Danish Grammy awards for their debut.

In 2000, the girls released their second album, Miracle, preceded by single S.O.A.P. Is In The Air. During preparations for their third album, S.O.A.P. decided to disband to try other things.

In 2010, Line released her first solo album under the artist name Saseline.