Two people are responsible for the classical guitar as it is known today. The first was the brilliant guitar-maker Antonio Torres. Torres revolutionized the process of building a guitar, making a careful study of how it made its sound, where the sound came from, and how he could improve it. The other was the Spanish virtuoso Francisco Tarrega.

Dionisio Aguado (1784–1849), a Spanish classical guitarist and composer, invented the tripodison, a guitar accessory used to hold the guitar instead of letting it rest on the right leg. This minimized the damping effect of the guitarist's body on the guitar's back and sides.

The Torres guitar, developed between the 1850s and the 1890s, had more volume than previous designs. It included a larger, deeper body and an aesthetically pleasing shape that is familiar today. Torres was the first maker to use “fan” bracing underneath the top. He once built a guitar with a spruce top and papier-mâché back and sides to prove his theory that it was the top that produced most of the volume.

Tarrega adopted the newly designed instrument and composed and arranged hundreds of pieces for it. Ironically, Tarrega did not perform much in public. He was, however, an influential teacher, with a close circle of students and friends who acted almost like disciples in the world outside Tarre-ga's home and studio.

And then, at the dawn of the twentieth century, there arrived a young, self-taught musician named Andrés Segovia. Before Segovia, people believed it was not possible for a solo guitarist to perform effectively to a large audience in a concert hall. Since Segovia, the world has become filled with guitarists in concert. In 1924, he made his debuts in London and Paris. He performed, transcribed, taught, and discovered a tremendous amount of music for the guitar. He also encouraged many composers to write for the instrument. He managed to reawaken the public interest in the music of J. S. Bach, and he arranged many Bach pieces for the guitar, which he also performed and recorded.

In addition to the modern guitar shape, Torres also created some experimental guitars. For example, to prove that it was the top and not the back or sides of the guitar that made the sound, Torres built a guitar with a papier-mache back and sides. Torres also invented a guitar that could be assembled (without glue) and then disassembled to fit into a shoebox.

Of Segovia's many gifts to the world, perhaps his most lasting was to make the guitar the popular instrument of the twentieth century. He also standardized the way guitar fingering is notated on scores (by showing the string number written within a circle over a series of notes that could be played elsewhere on the instrument), and settled the debate among classical guitarists about nails versus fingertips (by popularizing the use of plucking the strings with the nails of the right hand). By traveling and performing throughout the world, Segovia brought respect and recognition to the instrument and left behind a vast body of work and pupils who have gone on to become maestros in their own right.