Selma Ottilia Lovisa Lagerlöf (Swedish pronunciation: [ˈsɛlma ˈlɑːɡərˌløːv] ( listen); 20 November 1858 – 16 March 1940) was a Swedish author. She was the first female writer to win the Nobel Prize in Literature, and most widely known for her children's book Nils Holgerssons underbara resa genom Sverige (The Wonderful Adventures of Nils).

Born at Mårbacka (now in Sunne Municipality) an estate in Värmland in western Sweden, Lagerlöf was the daughter of Lieutenant Erik Gustaf Lagerlöf and Louise Lagerlöf née Wallroth. The couple's fourth child, she was born with a hip injury. An early sickness left her lame in both legs, although she later recovered. She was a quiet child, more serious than others her age, with a deep love of reading. The sale of Mårbacka following her father's illness in 1884 had a serious impact on her development.

Lagerlöf worked as a country schoolteacher at a high school for girls in Landskrona from 1885 to 1895 while honing her story-telling skills, with particular focus on the legends she had learned as a child. Through her studies at the Royal Women's Superior Training Academy in Stockholm, Lagerlöf reacted against the realism of contemporary Swedish language writers such as August Strindberg. She began her first novel, Gösta Berling's Saga, while working as a teacher in Landskrona. Her first break as a writer came when she submitted the first chapters to a literary contest, and won a publishing contract for the whole book. She received financial support of Fredrika Limnell, who wished to enable her to concentrate on her writing.