Lisi Harrison (born Elyse E. Gottlieb on July 29, 1970) is a Canadian-American novelist best known for her young adult fiction series. Her most notable works include The Clique, Alphas, and Monster High. Harrison's books have achieved significant commercial success, with The Clique series selling more than eight million copies worldwide and spending over two hundred weeks on the New York Times bestseller list.

Before becoming a full-time author, Harrison worked at MTV Networks as a senior director of development. In 2003, she left MTV to write full-time. Aside from her popular The Clique series, her novel The Dirty Book Club marked her first foray into adult fiction in 2017.

In recent years, Harrison has continued to expand her repertoire with new middle-grade series such as Girl Stuff and The Pack, and is currently collaborating on a middle-grade series called Graveyard Girls with Daniel Kraus.

Lisi Harrison resides in Laguna Beach, California, where she also conducts workshops called "Drama Free Friend" to help kids and their parents foster healthy, drama-free friendships.