Italo-Ethiopian War, 1935–36, a war in which Italy conquered Ethiopia and annexed it to its colonial empire. By failing to halt Italy, the League of Nations demonstrated it had neither the means nor the will to stop aggression. The Fascist dictators, Adolf Hitler of Germany and Benito Mussolini of Italy, were emboldened to attempt new conquests.

Italian colonial expansion in Africa during the late 19th century had resulted in a war with Ethiopia (also called Abyssinia) in which Italian forces were badly defeated at Aduwa in 1896. Subsequent treaties failed to define the boundaries between Eritrea, an Italian colony, and Ethiopia. A border incident in 1934 was seized on by Mussolini to make demands on Ethiopia.

The resulting dispute was brought to the League of Nations by Haile Selassie, emperor of Ethiopia, but negotiations were spurned by Italy, which invaded Ethiopia in the fall of 1935. The League imposed an embargo against Italy, but it excluded coal and oil and had little effect. The Italian northern army was commanded first by General Emilio de Bono and (after November 28) by Marshal Pietro Badoglio. A subordinate southern army was led by General Rodolfo Graziani. Addis Ababa, the capital, fell on May 5, 1936. On May 9 King Victor Emmanuel III was proclaimed emperor of Ethiopia. Ethiopia was attached to Eritrea and Italian Somaliland to form Italian East Africa.

Haile Selassie escaped May 3 on a British warship. On June 30 he made an eloquent plea before the League of Nations for military sanctions against Italy. Instead the League lifted the embargo in July.