Neck-through or neck-thru (or in full form neck through body) is a method of electric guitar or bass guitar construction that involves extending the piece (or pieces, in a laminate construction) of wood used for the neck through the entire length of the body, essentially making it the core of the body. The strings, fretboard, pickups and bridge are all mounted on this piece. So-called "ears" or "wings" (i.e. side parts of the body) are glued or laminated to the central "stick". The "wings" may be bookmatched in order to give a symmetrical appearance, and are often cut from one piece of wood.

"The Log" (built by Les Paul) can be considered as a forerunner of neck-thru, as he built it by using a 2x4 piece of pine as the neck and body core, and mounted the disassembled part of an archtop onto it.