Abstract: A foldable guitar includes a body having a base, a neck, a head and multiple strings. A first board is an elongate board and pivotably connected to the rear side of the body. The first board can be located overlapped and parallel to the body. The first board has a recess defined in one end thereof and the recess so as to accommodate a user's arm. A second board is an elongate board and pivotably connected to the rear side of the body. The second board can be located overlapped and parallel to the body. The second board has a protrusion which is received in the recess. The first and second boards can be folded to the rear side of the body to save storage space, or to be arranged according to different users' need.