Douglas made history in London at the 2012 Summer Olympics when she became the first African-American to win the gold medal in the all-round individual gymnastics competition.
Douglas told the magazine the book will detail how much she and her family overcame to achieve her Olympic dream.
Douglas, who took home two Olympic gold medals, left her family in Virginia to train in Iowa when she was 12 years old.
The book, Grace, Gold and Glory, My Leap of Faith will be published by the Zondervan division of HarperCollins in December.