The prize committee added that "in her deeply felt empathy with people in difficulty, she shows ways in which weakness can be turned into strength. Humanism and sympathy permeate and unify her artistry."
The prize, which has been given since 2003, is the world's biggest award for children's literature, and comes with a check for five million kronor or about 700,000 US dollars.
Crowther told Swedish public service radio Ekot " Wow..it's like a huge gift and I don't know really what to do with it."
A total of 167 people were nominated for this year's award.