A Deadhead or Dead Head is a fan of the American rock band the Grateful Dead. In the 1970s, a number of fans began travelling to see the band in as many shows or festival venues as they could. With large numbers of people thus attending strings of shows, a community developed. Deadheads developed their own idioms and slang.

Much Deadhead-related historical material received or collected by the band over the years is housed in the Grateful Dead Archive of University of California, Santa Cruz. Archive founding curator Nicholas Meriwether, who has also written extensively about the culture and its impact on society, predicted, "The Grateful Dead archive is going to end up being a critical way for us to approach and understand the 1960s and the counterculture of the era... It's also going to tell us a lot about the growth and development of modern rock theater, and it's helping us understand fan culture."