Bicycle messengers are people who work for courier companies carrying and delivering items by bicycle. Bicycle messengers are most often found in the central business districts of metropolitan areas. Courier companies use bike messengers because bicycle travel is less subject to unexpected holdups in city traffic jams, and is not deterred by parking limitations, fees or fines in high-density development that can hinder or prevent delivery by motor vehicle, thereby offering a predictable delivery time.

A courier is a person or organization that delivers a message, package or letter from one place or person to another place or person. Typically, a courier provides their courier service on a commercial contract basis; however, some couriers are government or state agency employees.