Electro-Harmonix is a New York-based company that makes high-end electronic audio processors. The company was founded by Mike Matthews in 1968. They are most famous for a series of popular guitar effects pedals introduced in the 1970s and 1990s.

Electro-Harmonix offers a full range of pedals capable of many different types of sound manipulation suitable for guitar, bass, vocal and keyboard signals, as well as other instruments. Legendary products include the Big Muff, Memory Man and Holy Grail series of pedals.