A jazz standard is a jazz tune that is held in continuing esteem and which is widely known, performed, and recorded among jazz musicians as part of the jazz musical repertoire. There is no definitive list of jazz standards, and the list of songs deemed to be "jazz standards" changes over time. Moreover, there are different jazz standards for the different musical styles and subgenres that make up jazz, such as swing, bebop, and fusion.

In many cases, songs that have become jazz standards were not originally composed by a jazz musician. Instead, they were used as the foundation for jazz arrangements, reharmonization, or improvisation by jazz performers or composers. Nevertheless, the songs commonly included in jazz fake books (books containing the melodies and chords to jazz songs) and those that have been widely recorded are a rough guide to the list of jazz standards.

Many jazz standards have a long history, and they are based on old popular tunes, Broadway or musical selections, or old recordings of famous bands from the Great American Songbook. In some cases, the version of a song that becomes a jazz standard is a reharmonized or altered version of the original song. Jazz musicians also include a wide range of 1950s and 1960s Bebop and Hard Bop tunes in their standards.

The development of a repertoire of jazz standards has created a shortlist of songs that are widely known by jazz musicians from different countries and jazz subgenre traditions. This shortlist makes it easier for jazz musicians to flesh out their song list for performances, or improvise over in familiar chord changes during jam sessions with musicians that they have just met. As well, the jazz standard repertoire is often performed by "working musicians" who play in bars, lounges, and supper clubs.