While the six string guitar has been more or less the standard instrument since the mid-19th century, guitarists and luthiers have experimented with additional strings to extend the range of the instrument practically since the emergence of the modern guitar form, sometime in the 15th century. Seven, eight, nine, ten and more strings have been used by guitarists seeking to increase the range of pitches available from the instrument. Some of these guitars are ethnic instruments, specific to different cultures such as Russian and Brazilian guitars. During the 90's the seven-string guitar became popular among metal bands such who used the additional string for extra low end. Extended range classical guitars (especially 8- and 10-string instruments) are being seen more frequently and have found favor with guitarists who play Renaissance and Baroque lute music, as well as those who wish to transcribe piano and orchestral works for the guitar.
There are some classical players of the seven-string guitar who also use an extended treble range by adding more frets at the high end (similar to some Viennese guitars of the 19th century.)
This is a list of guitarists who have made notable usage of extended-range guitars or have played a specifically notable instrument. This list does not include multi-neck guitarists or harp guitarists.