Abstract: The guitar string holder can effectively convert a twelve-string guitar into either a six-string guitar or a Nashville guitar by lowering six of the twelve strings below the operative plane. The base of the guitar string holder fits onto the body or through a slot in the top of the guitar for solid top designs, or fits into the sound hole and is held upward against braces located beneath the top surface of the guitar. Alternatively, the guitar string holder can be slid onto opposing edges of the sound hole. When the base is slid onto opposing edges of the sound hole, a frictional fit is achieved and wood screws are not needed. Six arms extend from the base of the guitar string holder and accommodate corresponding hooks. Each hook can hold one of the guitar strings beneath the operative plane. It is also possible to use the guitar string holder to hold selected strings, to thereby provide a standard six-string guitar and a Nashville guitar pretuned to different open tunings.