Hardcore punk (often referred to simply as hardcore) is a music genre that originated in the late 1970s, following the mainstream success of punk rock. Hardcore is generally faster, thicker, and heavier than earlier punk rock. The origin of the term "hardcore punk" is uncertain. The Vancouver-based band D.O.A. may have helped to popularize the term with the title of their 1981 album, Hardcore '81.

Hardcore has spawned the straight edge movement and its associated submovements, hardline and youth crew. Hardcore was heavily involved with the rise of the independent record labels in the 1980s, and with the DIY ethics in underground music scenes. It has influenced a number of music genres which have experienced mainstream success, such as alternative rock, metalcore, grunge, thrash metal, emo and post-hardcore.

Hardcore sprouted underground scenes across the United States in the early 1980s — particularly in Washington, D.C., California, New York/New Jersey, and Boston—as well as in Canada and the United Kingdom.