Steel guitar normally refers to any guitar where a significant part of the instrument is made out of stainless steel or some other metal.

The term should not be confused with steel strung guitar which is a normal acoustic guitar that has metal rather than nylon or cat-gut strings (the strings are not made out of steel though).

The most common type is the Dobro style guitar which features a metal cone where the sound hole would normally be. Extreme versions of this type of guitar may feature the entire body made out of steel (as shown on the cover of the Dire Straits album Brothers in Arms).

Less common are the lap steel guitar and its descendant, the pedal steel guitar.