Karen McCullah Lutz is an American screenwriter and novelist.

McCullah Lutz was born in the Philippines, where her father had been assigned with the United States Navy performing counterespionage duties, and grew up in Bergen County, New Jersey.

As a high school student, she maintained in her diary 10 Things I Hate About Anthony, her boyfriend at the time, which ultimately led to the title of her 1999 film, 10 Things I Hate About You. She wrote most of the published screenplays with her screenwriting partner Kirsten Smith.

In 2006 she wrote also her first novel The Bachelorette Party.