The Ndjamena-Djibouti Highway or TAH 6 is Trans-African Highway 6 in the transcontinental road network being developed by the United Nations Economic Commission for Africa (UNECA), the African Development Bank (ADB), and the African Union, connecting the Sahelian region to the Indian Ocean port of Djibouti in the country of Djibouti.

Consequently, travel through that area and Sudan–Chad border region is unsafe and development of that road section is at a standstill.

The route has a length of 4,219 km (2,622 mi) crossing Chad, central Sudan and northern Ethiopia.

Mountainous terrain in Ethiopia presented challenges to highway engineers.

The approximate route of the two highways follows a route originally proposed in the French Empire of the late 19th and early 20th centuries, and earlier French attempts to control the transcontinental crossing led to the Fashoda Incident.