The guitar is from origin a European instrument, it was developed in the medieval period, mainly in Italy, France and of course Spain. The name guitar comes from the Spanish word guitarra, which comes from the Arabic word qitara which is derived from the Persian word sihtar.
The guitar is descended from a couple of old instruments, among them the old Roman cithara, the four string oud from the Moors, and the Scandinavian lut, or lute.
In the 13th century there were 2 types of guitar, the Moorish guitar with a rounded back and pretty wide neck, and the Latin guitar which looked already like the modern guitar.
In the 15th century these instruments had developed in to something called guitar. Some instruments were played with a bow; this of course led to the development of the violin.
In the next centuries the guitar developed into what we now call an acoustic guitar, it is only in the 20th century that the development of the electric guitar took place.
Visit The Guitar Classroom if you want to learn to play guitar