The Manchukuo National Railway was the state-owned national railway company of Manchukuo. Generally called the "國線", it was controlled by the Manchukuo Ministry of Transportation and had its lines primarily in the central and northern parts of the country. In local newspapers it was simply referred to as "國鉄". It was built, operated and managed by the South Manchuria Railway, a state-owned national railway company of the Empire of Japan, of which the Kwantung Army frequently intervened in its affairs.

Manchukuo was a puppet state of the Empire of Japan in Northeast China that existed from 1932 until its dissolution in 1945. It was ostensibly founded as a republic, its territory consisting of the lands seized in the Japanese invasion of Manchuria; it was later declared to be a constitutional monarchy in 1934, though very little changed in the actual functioning of government. Manchukuo received limited diplomatic recognition, mostly from states aligned with the Axis powers, with its existence widely seen as illegitimate.