An expression pedal is a dynamic control device that allows musicians to manipulate various effects in real time by adjusting parameters with their foot. Unlike a standard effects pedal with on/off switches or knobs, an expression pedal provides continuous control over settings such as volume, wah, delay time, modulation depth, or gain, depending on the connected effect unit.

Expression pedals are commonly used with multi-effects processors, digital delays, and modulation pedals, offering hands-free adjustments for greater musical flexibility. Some well-known expression pedals include the Boss EV-30, Mission Engineering EP-1, and the Dunlop DVP4, all of which provide smooth, responsive control over a wide range of effects, making them essential for live performances and dynamic playing styles.