Avi was born Edward Irving Wortis in 1937 in New York City and was raised in Brooklyn, New York. His twin sister called him Avi, and the name stuck. Avi had a learning disability called dysgraphia, which caused him to reverse or misspell words, but nonetheless he was determined to be a writer. He first tried to be a playwright, and began writing for young people after his son Shaun was born. He is a winner of the Newbery Medal and twice one of the runners-up