A milling machine is a tool used to machine solid materials into precise shapes. Milling machines are often identified as two basic types. The two basic configurations are vertical and horizontal. However, there are alternate classifications according to method of control, size, purpose and power source.

Both types of milling machine range in size from small, bench-mounted devices to large industrial-sized machines. Unlike a drill press, which holds the workpiece stationary as the drill penetrates the material, milling machines also move the workpiece radially against the rotating milling cutter, which cuts on its sides as well as its tip. The workpiece and cutter movement are precisely controlled, usually by means of precision ground slides and leadscrews or analogous technology.

Milling machines may be manually operated, mechanically automated, or digitally automated via computer numerical control (CNC).