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 to that point, 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.