Knox, 24, was found guilty of the 2007 slaying of her British roommate in Perugia where both were foreign exchange students sharing a cottage.
The American college student's 2009 conviction was overturned and she was freed in October.
"Aided by journals she kept during her imprisonment, Knox will talk about her harrowing experience at the hands of the Italian police and later prison guards and inmates," HarperCollins said in a statement Thursday. "She will reveal never-before-told details surrounding her case and describe how she used her inner strength and strong family ties to cope with the most challenging time of her young life."
The as-yet-untitled memoir is scheduled to be published in 2013.
The Hollywood Reporter said Knox will be paid $4 million for the book.