The Mamiya C series is a line of twin-lens reflex medium-format system cameras manufactured by Mamiya between 1956 and 1994. It was developed from the Mamiyaflex series of cameras built from 1949 to 1956. The Mamiya C series was initially aimed at the professional market, but some later models were intended for amateurs.

Unlike most TLR cameras, the Mamiya C has interchangeable lenses. The upper and lower lenses come off as a unit, and are available in at least seven different focal lengths. The lower lens of each unit has an aperture diaphragm as well as a leaf shutter. A flash sync terminal is part of the lens unit, and the delay can be set to M or X mode. The camera has an interlocking baffle that enables lenses to be changed without exposing the film.

Focusing is performed via a bellows system on the front side of the camera. Early models had separate film advance and shutter cocking mechanisms; on later models the shutter was automatically cocked as the film was advanced. There is no metering in the camera body, so an external light meter is necessary; later models were compatible with optional accessory viewfinders that had built-in meters.