Tamora Pierce was born in South Connellsville, Pennsylvania in Fayette County, on December 13, 1954. Her mother wanted to name her "Tamara" but the nurse who filled out her birth certificate misspelled it as "Tamora". When she was five her sister Kimberly (whom she based Alanna on) was born and a year later her second sister, Melanie, was born. From the time she was five until she was eight, she lived in Dunbar. In June 1963 she and her family moved to California. They first lived in San Mateo on El Camino Real and then moved to the other side of the San Francisco Peninsula, in Miramar. They lived there for half a year, in El Granada a full year, and then three years in Burlingame.
She began reading when she was very young and started writing at about 6 years old. Her interest in fantasy and science fiction began when she was introduced to J. R. R. Tolkien's The Lord of the Rings, and so she started to write the kind of books that she was reading. After her parents divorced, her mother moved her and her sisters back to Fayette County in 1969, where she spent two years at Albert Gallatin Senior High. When her family moved again, she spent her senior year at Uniontown Area Senior High School, acting, singing, and writing for the school paper.
While at the University of Pennsylvania she wrote the books that became The Song of the Lioness quartet. The first book of this quartet, Alanna: The First Adventure was published by Atheneum Books in 1983.
Pierce lived with her husband Tim Liebe (Spouse-Creature) in upstate New York, with their four cats and multiple other pets, until they moved to Syracuse, New York.
In 2008, she donated her archive to the department of Rare Books and Special Collections at Northern Illinois University.