An archtop guitar is a steel-stringed hollow body acoustic or electric guitar with a distinctive "arched" belly and a sound particularly suited to blues and jazz.

Archtops are also known as jazz-boxes or hollow bodies, although not all hollow body guitars are archtops. The line between the two main types of electric guitar, hollow body and solid body, is not always easy to draw. All electric arch top guitars are hollow bodies, but not conversely.

The top (and often the back) of the archtop guitar are either carved out of a block of solid wood or heat-pressed using laminations, and it normally has f-holes. The arching of the top and the f-holes are both similar to the violin family, on which they were originally based. Although any true archtop has a rich tone unamplified, most archtop guitars have some sort of pickup/microphone system, and many are intended primarily for this purpose and so are semi-acoustic electric guitars. Most pickups on modern archtops are humbuckers placed in bridge and/or neck positions.

The archtop guitar was invented by Lloyd Loar of the Gibson Guitar Corporation after his design of a similar style of mandolin.

Archtop guitars were immediately adopted upon their release by both jazz and country musicians and have remained particularly popular in jazz music, usually using thicker strings (higher gauged round wound and flat wound) than conventional acoustic guitars. The electric hollow body archtop guitar has a distinct sound among electric guitars and is consequently appropriate for many styles of rock and roll. Many electric archtop guitars intended for use in rock and roll are equipped with a tremolo arm, most often of the Bigsby type.

The most famous archtop guitars were the factory-made instruments by Gibson and Epiphone, and the highly prized handmade creations of luthiers such as D'Angelico, Stromberg, Wilkanowski, and D'Aquisto. More recently, interest in archtops has been revived by luthiers such as Bob Benedetto. The Benedetto style of acoustic/electric archtop has been copied by luthiers such as Dale Unger, John R. Zeidler, Dana Bourgeois and others. Most of the accessories (pickguard, bridge, tuner buttons, knobs, etc.) are made of wood (ebony or rosewood) instead of metal and have a clean acoustic look. More ordinary brands (all of them quite good instruments) are Yamaha, Epiphone (owned by Gibson), Eagle, Jay Turser and others.

Some archtop guitars have Bigsby or other tremolo arm systems. Most tremolo systems cannot be fitted to an archtop owing to the need to cut large holes in the belly to accommodate the mechanism, but the Bigsby and the Gibson Vibrola can both be fitted.

Guitar players choose archtops mainly because they offer the warm rich sound of an acoustic guitar and of course a "real" sustain sound. The electric archtop will enable the player to combine the magnificent sound with different amplifiers and effects.