Catherine Johnson is a British playwright, producing works for stage and television. She is best known for her book for the ABBA-inspired musical Mamma Mia! and screenplay for the musical's film adaptation. The film became the highest-grossing British picture of all time in the UK, and the biggest selling UK DVD of all time in January 2009. She also co-wrote the 2018 sequel, Mamma Mia! Here We Go Again.

Mamma Mia! is a jukebox musical written by British playwright Catherine Johnson based on songs recorded by Swedish group ABBA and composed by members Benny Andersson and Björn Ulvaeus. The musical's title is taken from the group's 1975 chart-topper "Mamma Mia". Ulvaeus and Andersson were involved in the development of the show from the beginning, while singer Anni-Frid Lyngstad was involved financially in the production and also appeared at many of the premieres around the world.