Karlsson-on-the-Roof is a character who figures in a series of children's books by the Swedish author Astrid Lindgren. Lindgren may have borrowed the idea for the series from a similar story about Mr. O'Malley in the comic strip Barnaby (1942) by Crockett Johnson.

Astrid Anna Emilia Lindgren was a Swedish writer of fiction and screenplays. She is best known for several children's book series, featuring Pippi Longstocking, Emil of Lönneberga, Karlsson-on-the-Roof, and the Six Bullerby Children, and for the children's fantasy novels Mio, My Son; Ronia the Robber's Daughter; and The Brothers Lionheart. Lindgren worked on the Children's Literature Editorial Board at the Rabén & Sjögren publishing house in Stockholm and wrote more than 30 books for children. In 2017, she was calculated to be the world's 18th most translated author. Lindgren had by 2010 sold roughly 167 million books worldwide. In 1994, she was awarded the Right Livelihood Award for "her unique authorship dedicated to the rights of children and respect for their individuality." Her opposition to corporal punishment of children resulted in the world's first law on the matter in 1979, while her campaigning for animal welfare led to a new law, Lex Lindgren, in time for her 80th birthday.