Post Rock is a genre of alternative rock characterized by the use of musical instruments commonly associated with rock music, but using rhythms, harmonies, melodies, timbre, and chord progressions that are not found in rock tradition. Simply put, it is the use of 'rock instrumentation' for non-rock purposes. Practitioners of the genre's style typically produce instrumental music.

As with many musical genres, the term is arguably inadequate as a concise descriptor: for example, Don Caballero and Tortoise were among the more prominent bands of the 1990s described as post rock, but the two bands' music has very little in common besides the fact that they are both largely instrumental. As such, the term has been the subject of backlash from listeners and artists alike.

Although firmly rooted in the indie or underground scene of the 1980s and '90s, post-rock's style often bears little resemblance musically to that of indie rock.