Olancho is one of the 18 departments into which the Central American nation of Honduras is divided. It is the largest of all the departments, and Hondurans frequently point out that the department is larger than the neighboring Republic of El Salvador. In the eighteenth and nineteenth centuries, Olancho resisted government authority from Tegucigalpa to the point of causing a civil war. To this day, the old independent sentiments persist among Olanchanos, although the department's role as an agricultural producer has made it an integral part of the Honduran economy. The current president of Honduras, Porfirio Lobo, hails from the department, specifically from the city of Catacamas.

The departmental capital is Juticalpa.

Rugged mountains rise in the western and northern portions of the department, notably the Sierra de Agalta, the Montaña de Tembladeros, and the Montaña de Botaderos. Vast pine and hardwood forests cover these mountains. Central Olancho has rolling plains, watered by the Guayape River and its affluents. These plains, sometimes called pampas due to their similarity to the vast Argentinian plains, are famous for their large cattle herds and extensive farming. The main cities, Juticalpa and Catacamas, are located there. The eastern part of the department is covered with rainforests, though the influx of impoverished, farmers and intense timber extraction have increased deforestation rates in the area. A portion of the Rio Platano Biosphere Reserve, a tropical rainforest with diverse wildlife and declared a World Heritage site by UNESCO, straddles the border of Olancho and the neighboring departments of Gracias a Dios (department) and Colón (department).