Glassjaw is an American post-hardcore band from Hempstead, New York. It was formed in 1993 by vocalist Daryl Palumbo and guitarist Justin Beck. The band is known for their intense live shows, as well as their frequent line-up changes. Despite their limited commercial success and small discography, they are considered to be one of the most influential bands in the progression of the underground music scene in the eastern United States and United Kingdom for the post-hardcore genre.