Wadi Howar (Wadi Howa) is a wadi in Sudan and Chad. It travels approximately 400 kilometres in a northeasterly direction from the Ouaddaï highlands in Chad across the North Darfur state of Sudan, before losing itself in the Libyan Desert. Towards its western end it forms a part of the international boundary between Sudan and Chad, separating the West Darfur state of Sudan and the Borkou-Ennedi-Tibesti Region of Chad.