Crowther writes mainly in French
Belgian illustrator and author Kitty Crowther has won the 2010 Astrid Lindgren Memorial award, which honours the best in children's writing.
The award, named after the Swedish creator of Pippi Longstocking, brings with it prize money of 5m kroner (£461,724).
Crowther has written and contributed to more than 35 children's books and writes mostly in French.
The jury described her as "the master of the line".
Crowther's main works are picture books, including L'enfant racine (The Root Child) and La visite de petite mort (The Visit of Little Death).
Jury chair Larry Lempert said: "She's a traditional storyteller. It's her way of telling that takes people between imagination and reality."
Mr Lempert described Crowther as, first and foremost, an illustrator and then an author, praising her use of simple materials and tools to illustrate books.
"In Kitty Crowther we found an artist and storyteller strong in her humanity and sympathy... she follows the weak, she shows ways of life," he said.
Crowther said the award was "a fantastic recognition from Swedish culture". She will receive her prize at a ceremony in Stockholm on 1 June.
The award was set up by the Swedish government following the death of Lindgren in 2002. Her enduring Pippi Longstocking character has been published for generations around the world.