The Chapman Stick is an electric musical instrument devised by Emmett Chapman in the early 1970s. A member of the guitar family, the Chapman Stick usually has ten or twelve individually tuned strings and is used to play bass lines, melody lines, chords, or textures. Designed as a fully polyphonic chordal instrument, it can also cover several of these musical parts simultaneously.

The Stick is available with passive or active pickup modules that are plugged into a separate instrument amplifier. With a special synthesizer pickup, it can be used to trigger synthesizers and send MIDI messages to electronic instruments.

Imagine creating music on a stringed instrument that is simultaneously a guitar, a bass, a piano, and percussion. Add unlimited electronic capabilities and forward-thinking playing techniques for ultimate expression. Now, design a tuning to make navigation of the instrument amazingly simple, and streamline the look and feel for optimal accessibility. This instrument already exists as the Chapman Stick.

— Steve Adelson describing the Chapman Stick in Guitar Player magazine

A Stick physically resembles the fretboard of an electric guitar. It is, however, considerably longer and wider and is strung with 8, 10, or 12 strings. While the electric guitar is usually played by strumming or plucking the strings, the Chapman stick is usually played by tapping or fretting the strings. Instead of one hand fretting and the other plucking, as is typical with the guitar, the Chapman stick player uses both hands to sound notes by striking the strings against the fingerboard "behind" (in guitar parlance, this means a short distance towards the tuning machines) or on the appropriate frets for the desired notes. For this reason, the Chapman stick can sound many more notes at once than some other stringed instruments, making it more comparable to a keyboard instrument in terms of polyphony. This arrangement lends itself to playing many lines at once, and many Stick players have mastered performing bass, chords, and melody lines simultaneously.

Typically, the Chapman Stick is held via a belt-hook and a shoulder strap. The player hooks the instrument onto the belt and places the head and dominant arm through the shoulder strap. The instrument then settles into a position approximately 30 to 40 degrees from vertical, which allows both of the player's hands to naturally and comfortably address the fretboard. The player then hammers onto the strings with the fingertips in the same way that one would strike a piano key. The technique is very similar to that of the piano inasmuch as the player covers both bass and melody notes together with both hands, and each note is struck with one finger of one hand. Typically, one hand plays the melody on the treble strings and the other plays rhythm on the bass strings.

A seated playing position (which keeps the Stick in a similar playing position relative to the player as the standing position) is also popular, wherein a cross-member is laid upon the knees of the seated player and the stick's belthook rests upon the crossmember.

In 1969, jazz guitarist Emmett Chapman developed the two-handed tapping technique (in which both hands play parallel to the frets) and applied it to his playing. At the time, Chapman was playing a 9-string long-scale guitar, but decided to develop a new instrument for use with "free hands" to use the method's full potential. The Chapman Stick took five years to develop, during which Chapman also opted to set up a business to sell it. The first production model of the Stick was launched in 1974. On October 10 of the same year, Chapman brought his instrument to public attention by demonstrating it on the game show What's My Line?