KTX-II, or KTX-Sancheon, is a South Korean high-speed train built by Hyundai Rotem in the second half of the 2000s and operated by Korail since March 2009. With a top speed of 305 km/h (190 mph), the KTX-II is the first commercial high-speed train developed in South Korea.

When South Korea started its high-speed rail project, rolling stock and infrastructure was built in the framework of a technology transfer agreement between GEC-Alsthom (today Alstom), the main maker of French TGV high-speed trains, and South Korean companies. Thus Korea Train Express (KTX) began operating with KTX-I trains, which were derived from the TGV Réseau, and built both by Alstom and Rotem. The technology transfer agreement did not provide for a complete control of manufacturing processes, and construction involved the import of parts. To increase the domestic added value, in 1996, an alliance of South Korean government research agencies, universities and private companies started a project named G7 to develop domestic high-speed rail technology.