Jennifer Donnelly (born August 16, 1963) is an American writer best known for the young adult historical novel A Northern Light. The novel was published as A Gathering Light in the U.K. and won the 2003 Carnegie Medal for outstanding children's book. It was later named one of the top ten winning works for the 70th anniversary of the Medal. Additionally, it was listed as one of Time Magazine's 100 Best Young Adult Books of All Time in 2015.

Donnelly is the author of fourteen novels including Beastly Beauty, Poisoned, Stepsister, Lost in a Book, These Shallow Graves, Sea Spell, Dark Tide, Rogue Wave, Deep Blue, Revolution, The Tea Rose, The Winter Rose, The Wild Rose, and Humble Pie, a picture book for children. She is also a co-author of Fatal Throne, exploring the lives of King Henry VIII's six wives. In 2023, she published Molly's Letter, the first in a series of novella-length stories called Rose Petals.

Jennifer grew up in New York State, in Lewis and Westchester counties.