An Inlay (ɪ́nlè) is a primarily decorative technique, where a contrasting material is “laid” into the wood of the fretboard and/or headstock of a guitar. The most high-end material used to make inlays is mother-of-pearl, but inlays are also frequently made from plastic, wood or even LED fibers.

Most commonly, fretboard inlays are small circles, parallelograms or shark fin shapes. These marks, in addition to being esthetically pleasing, are  used to emphasize certain frets to make them easier for players to find quickly.

Headstock inlays are usually an embossed version of the guitar manufacturer’s logo or name but in some cases can be ornate designs. Additionally, some high-end guitars have elaborate and beautiful designs on the are around the sound hole, their backs and/or sides.