Klas Östergren (born 20 February 1955) is a Swedish novelist, screenwriter, and translator.

Östergren is a member of the Swedish Academy since 20 December 2014, succeeding Ulf Linde on seat 11. On 6 April 2018 he announced that he would no longer participate in the Academy's work, and in May 2018, the Academy announced that Östergreen and three other members had been allowed to formally resign. In 1999, he was nominated for the Guldbagge Award for Best Screenplay. In 2005, he received the grand prize bestowed by the country's premier literary society, Samfundet De Nio.