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

Östergren's works, which also includes acclaimed novels such as Den sista cigaretten (2009, "The last cigarette") and short stories, typically depicts odd characters that leads the narrator into a shadowworld of the official society where its own laws and rules is prevailing.

[5] As a writer of screenplays and teleplays, he was honored in 1999 when Veranda för en tenor [Waiting for the Tenor], the screen treatment (which he co-wrote with Lisa Ohlin) of a short story from Med stövlarna på och andra berättelser, was nominated for the Guldbagge Award for Best Screenplay (Sweden's equivalent of the Academy Award).

The first, 1996's Jerusalem, adapted from the novel by Selma Lagerlöf, was directed by her husband, Bille August, and the other, Offer och gärningsmän, was a 1999 miniseries directed for Sweden's national television broadcaster, SVT, by Tomas Alfredson.

[2] He has been awarded numerous Swedish literary prizes and his works have been translated to at least a dozen languages.