Margaret Colleen Hoover (née Fennell; born December 11, 1979) is an American author who primarily writes novels in the romance and young adult fiction genres. She is best known for her 2016 novel It Ends with Us. Many of her works were self-published before they were picked up by a publishing house. As of October 2022, Hoover has sold approximately 20 million books. She was named one of the 100 most influential people in the world by Time magazine in 2023.

Hoover is also known for being the founder of The Bookworm Box charity and Book Bonanza. Her social media username is @colleenhoover pretty much everywhere except her email, which is colleenhooverbooks@gmail.com.