The title "Spanish guitar" is a reference to the instrument's origin rather than the music played on it. It is also called the "nylon string guitar," "classical guitar," or "gut string guitar." It is certainly one of the most recognizable instruments in the world today, and its history can be traced back for approximately four centuries. Thanks to ancient carvings and statues, we know that instruments similar to the modern guitar have existed for at least 5,000 years. However, the Spanish guitar is believed to have evolved under the combined influences of the Renaissance five string guitar, the baroque guitar, the lute, and the vihuela.

The latter half of the Middle Ages was a very good time for the guitar. Thanks to the resurgence of human innovation, a variety of instruments were invented or improved upon. The Renaissance five string guitar, for example. This musical instrument, sometimes called a gittern, resembled a small lute and was carved from a single piece of wood with a curved peg box. The vihuela, another instrument of the period, was developed in Spain during the early sixteenth century. This instrument had six double strings made of gut and was tuned almost exactly like the modern Spanish guitar. Finally the baroque guitar, or early romantic guitar, was developed in Italy in the late sixteenth century. It, too, was a six-stringed instrument. In looking at the attributes of each, it is evident that all of these instruments eventually combined and evolved into the Spanish guitar. Our modern instrument, like several of its predecessors, has six strings (usually) and is an acoustic instrument that utilizes a soundboard as a resonator. It uses nylon strings, which are similar to the earlier gut strings in that they are fairly low tension, especially in comparison to their steel cousins.

As previously stated, the reference to Spain in the term "Spanish guitar" is a nod to the instrument's repertoire. Not surprisingly, given its family history, music for the Spanish guitar includes not only that written specifically for the instrument but that written for the vihuela, lute, baroque guitar, and Renaissance guitar as well. It is even possible to use the Spanish guitar to play music originally written for the violin and cello, as is sometimes done with the compositions of Johann Sebastian Bach.

The earliest music written specifically for the Spanish guitar dates from the late eighteenth century and corresponds to addition of the instrument's sixth string. However, it was not until the middle of the nineteenth century that the Spanish guitar began to establish its own unique genre. Francisco Tarrega was central to this movement and is credited with incorporating some aspects of flamenco into his composition. It was at this time that Spain was establishing itself as a force in music, and the guitar was central to the country's reputation in Europe.

Today, the Spanish guitar remains a popular instrument all over the Western world. It has become widely used in popular music and rock and roll, a trend sometimes credited to Mason Williams' ever popular 1968 hit, Classic Gas.