A dimmer switch coupleable to a circuit including a power source, load, and single-pole double-throw three-way switch that comprises a first and a second fixed contact, and a movable contact. The three-way switch has a first state in which the movable contact is contacting the first fixed contact and a second state in which the movable contact is contacting the second fixed contact. The dimmer switch comprises first, second and third load terminals coupled in series with the three-way switch. The dimmer switch comprises first and second controllably conductive devices, such that the first and second controllably conductive devices are operable to conduct load current to control the amount of power delivered to the load when the three-way switch is in the respective first and second states; and a controller coupleable to the first and second controllably conductive devices for rendering the first and second controllably conductive devices conductive and non-conductive.