Liz Tuccillo is an American writer and actress best known for her work on the HBO comedy series Sex and the City and for co-authoring (with Greg Behrendt) the self-help book He's Just Not That Into You. Her first novel, How to Be Single, was published in June 2008.
As an actress, she was seen in the film Welcome to New York, in which she had one line.
Tuccillo is also the creator of the 2005 television series Related, which aired on the WB network. She directed and wrote the 2008 film Gone to the Dogs.