Brian K. Vaughan (born July 17, 1976) is an American comic book and television writer, best known for the comic book series Y: The Last Man, Ex Machina, Runaways, Pride of Baghdad, Saga, and Paper Girls.

Vaughan was a writer, story editor and producer of the television series Lost during seasons three through five. He was nominated for a Writers Guild of America Award for Best Dramatic Series at the February 2009 ceremony for his work on the fourth season. The writing staff was nominated for the award again at the February 2010 ceremony for their work on the fifth season. He was formerly the showrunner and executive producer of the TV series Under the Dome.

Wired describes Vaughan's comics work as "quirky, acclaimed stories that don't pander and still pound pulses". His creator-owned comics work is also characterized by "finite, meticulous, years-long story arcs", on which Vaughan comments, "That's storytelling, with a beginning, a middle, and an end. Something like Spider-Man, a book that never has a third act, that seems crazy." In 2007, Erik Malinowski, also of Wired, called Vaughan "the greatest comic book visionary of the last five years", comparing him to Frank Miller, Alan Moore, Paul Pope, and Steve Niles, and praised his addition to the TV series Lost as redeeming that series' third season.

For his writing, Vaughan has won 14 Eisner Awards, 14 Harvey Awards, and a Hugo Award.