A semi-acoustic guitar or hollow-body electric is a type of electric guitar with both a sound box and one or more electric pickups. This is not the same as an electric acoustic guitar, which is an acoustic guitar with the addition of pickups or other means of amplification, either added by the manufacturer or the player.

Other semi-acoustic or acoustic electric instruments include basses and mandolins. These are similarly constructed to semi-acoustic guitars, and are used in the same ways and with the same limitations.

Semi-acoustic instruments divide into two types:

• In some, the sound box is adequate for performance in its own right, and use of a pickup is optional as an alternative to using a microphone. Some manufacturers refer to these as acoustic electric rather than semi-acoustic instruments, but the terminology varies.

• More often, the instrument is designed primarily to be used with an amplifier, and the sound box is used primarily to produce an amplified tone not obtainable with a solid body instrument.

Some instruments are borderline between these two types. For example, some electric arch top guitars are physically and acoustically identical to models from the same company without pickups, but the electric versions are almost never seen in performance without an amplifier. So, although the instrument is demonstrably capable of use as an acoustic instrument, in practice this does not occur.

Other instruments are borderline between semi-acoustic and solid body. For example, some Telecaster guitars have chambers built in to an otherwise solid body to enrich the sound. Exactly where the line is to be drawn between a constructed sound box and a solid wooden body, whose construction also affects the sound according to many players, is not generally agreed.

Some models have a fully hollow body, others may have a solid centre block running the length and depth of the body (for instance the Gibson ES-335). Semi-acoustics are capable of producing a fuller and richer tone than most solid-bodied electric guitars, but are prone to feedback when played through an amplifier. Because semi-acoustic guitars can be connected to an amplifier, they can be played at a much louder volume than simple acoustic models. They are favourites of big band guitarists and jazz players particularly. Some companies that have produced famous semi-acoustic guitars include: Rickenbacker, Gretsch and Gibson. A variety of manufacturers now produce semi-acoustic model guitars.

Generally, hollow body electric guitars are usually lighter than a solid body guitar of comparative size because its body mass is reduced as a result of the addition of sound chambers. However, they face problems in high-gain amplification, as the sound chambers also induces unsavory feedback.

A few of the most famous manufacturers include Gibson, D'Angelico, Gretsch, Epiphone, Rickenbacker and Ibanez.

Image:Guitar Epiphone 01.jpg|The Epiphone Emperor "Joe Pass" Image:Rickenbacker 330JG.jpg|The Rickenbacker 330 JG

There are many well-known hollow body electric guitars. a few examples would be:

• The Gibson L5
• The Gibson ES-335 actually semi-hollow electric guitar, similar in appearance to hollow body Gibson ES-330
• The Ibanez Artcore Series Hollowbody guitar line
• The Gretsch White Falcon Electric Guitar
• The Rickenbacker 300 series
• The Epiphone Les Paul Ultra model