Piccolo bass can refer to two string instruments, one acoustic and one electric.

The acoustic piccolo bass is an instrument similar to the double bass, but with a range exactly one octave higher.

The electric is a string instrument very similar to a 4-string electric bass guitar, but usually tuned one octave higher than a normal bass. This results in the lowest note from a piccolo bass being equal to the E found on the 7th fret of the A string on a standard bass. To allow such an uptuning, there are two options. Either the strings can be thinner or the length of the neck (the scale) can be shorter. The first option is the most common and several companies manufacture piccolo sets that can be put on any regular bass, thereby converting any bass into a piccolo bass.