Abstract: The orifice chemical vapor deposition reactor provides controlled and regulated reaction gas and vapor flow in order to produce high yields of carbon nanotubes with relatively high purity. The reactor includes a first reaction chamber having an inlet and an outlet, with an input gas being injected therein. A catalyst boat is received within the first reaction chamber for receiving a volume of reaction catalyst. A second reaction chamber is provided, having an inlet and an outlet. The inlet thereof is in fluid communication with the outlet of the first reaction chamber. A flow-regulating member is positioned within the second reaction chamber adjacent the inlet thereof, with the flow-regulating member having an orifice formed therethrough for regulating gas flow. At least one product boat is received within the second reaction chamber for receiving at least one substrate upon which carbon nanotubes are formed.