A 1965 Gibson Maestro Fuzz Tone FZ-1A, one of the first commercially available fuzz boxes.

A fuzzbox is a type of stomp box comprising an amplifier and a clipping circuit, which generates a deliberately distorted version of the input signal. As opposed to other distortion guitar effect pedals, a fuzzbox boosts and clips the signal sufficiently to turn a standard sine wave input in to what is effectively a square wave output. This gives a much more distorted and synthetic sound than a standard distortion or overdrive. Fuzzboxes (or fuzz boxes) were the first distortion devices not based on vacuum tubes.

The generated signal is rich in extra harmonics of the input signal, particularly odd harmonics, and will also produce cross-modulation between any non-harmonic components of the input signal, leading to dissonance. For this reason, power chords are often used when using fuzzboxes, to reduce dissonance.

Early fuzzboxes used germanium transistors. By the end of the 1960s, these were replaced by silicon transistors. Today, some fuzzbox builders offer pedals with germanium transistors again.

The fuzzbox is associated with rock music, particularly artists such as Jimi Hendrix. Famous examples of fuzzboxes include the infamous "Fuzz Face" (originally made by the Arbiter Group), and the "Big Muff Pi" (made by Electro-Harmonix) series of pedals.

We've Got A Fuzzbox & We're Gonna Use It, commonly known just as Fuzzbox is also an all-women punk band.

"Fuzzbox Voodoo" is the name of a song from the "Antenna" album of ZZ Top.

"(I Can't Get No) Satisfaction" from the The Rolling Stones was the first hit to feature a fuzzbox, the Gibson FZ-1.