Greg Weeks is an American singer-songwriter based in Philadelphia. His music has been described as folk, acoustic, psychedelic and experimental. He is best known as a founding member of the psychedelic folk-rock band Espers. Weeks has released four solo albums and has guest-recorded with many artists, including Fern Knight and Marissa Nadler. He is also a member of The Valerie Project.

In 2007, he founded the record label Language of Stone, an imprint of Drag City, along with his wife Jessica Weeks.