The British expedition to Abyssinia was a rescue mission and punitive expedition carried out in 1868 by the armed forces of the British Empire against the Ethiopian Empire (also known at the time as Abyssinia). Emperor Tewodros II of Ethiopia, then often referred to by the anglicized name Theodore, imprisoned several missionaries and two representatives of the British government in an attempt to force the British government to comply with his requests for military assistance. The punitive expedition launched by the British in response required the transportation of a sizeable military force hundreds of kilometres across mountainous terrain lacking any road system. The formidable obstacles to the action were overcome by the commander of the expedition, General Robert Napier, who captured the Ethiopian capital, and rescued all the hostages.

Historian Harold G. Marcus described the action as "one of the most expensive affairs of honour in history."

By October 1862 Emperor Tewodros's position as ruler had become precarious: much of Ethiopia was in revolt against him, except for a small area stretching from Lake Tana east to his fortress at Magdala. He was engaged in constant military campaigns against a wide array of opponents. Likewise, Abyssinia was also threatened by the encroachment of Islam as Ottoman Turks and Egyptians invaded Ethiopia from the Red Sea and through Sudan. Tewodros wrote to the major powers for help. As Donald Crummey recounts, "Now came the definitive attempt, at the turning point of the Emperor's career. Success might stabilize the internal situation; defeat would pull out the last prop. He proposed to send embassies with the ultimate objective of obtaining military alliances and agreements for technical progress."

Tewodros sent letters to the Russian Empire, Prussia, the Austrian Empire, French Empire and the British Empire. The French government responded with demands on behalf of a Lazarist mission in Hamasien, at the edge of Tewodros's realm; they were the only country known to have responded. A former diplomat^[who?] has noted that factors beyond simple indifference may have limited the number, forcefulness, and speed of European powers' responses: The letter was in Amharic and was sent to Germany for translation^[which?].

Tewodros's letter to Queen Victoria appealed to Christian solidarity in the face of the Islamic expansion occurring throughout the region but this garnered little sympathy. The British Empire's interests in Northeast Africa were not geared towards a Christian "crusade" against Islam but instead, the British sought to cooperate politically, strategically and commercially with the Ottoman Empire, Egypt and the Sudan. This was not only to protect the route to India but also to ensure that the Ottoman Empire continued to act as a buffer against Russia's plans for expansion into Central Asia. Moreover, as a result of the American Civil War, deliveries of cotton from the Confederate States of America to the British textile industry were declining, making the British increasingly dependent on Egyptian-Sudanese cotton. In the view of these interests, the British Foreign Office did not look favourably on supporting Tewodros. The letter was preserved but not answered.

The first European to cross Tewodros' path after this lack of a response happened to be Henry Stern, a British missionary. Stern had also mentioned the Emperor's humble origins in a book he had published; although the reference was not intended to be insulting ("the eventful and romantic history of the man, who, from a poor boy, in a reed-built convent became...the conqueror of numerous provinces, and the Sovereign of a great and extensive realm") it proved to be a dangerous mistake. At the time Tewodros was insisting on the truth of his descent from the Solomonic dynasty, and Tewodros expressed his rage in many ways, including having Stern's servants beaten to death, and Stern, together with his assistant, a Mr Rosenthal, were "chained, severely treated, and the latter thrashed on several occasions."

The British consul Charles Duncan Cameron, along with the Abuna Salama III and the group of missionaries based at Gafat, all interceded for the release of the imprisoned pair, and for a while it appeared that their efforts might succeed; but on 2 January 1864 Cameron was seized along with his staff, and all were put in chains. Shortly afterwards, Tewodros ordered most of the Europeans in the royal camp put into chains.

The British government sent Hormuzd Rassam, an ethnic Assyrian Christian from Mesopotamia, to negotiate a solution to this crisis, but "security in Tigre, the King's indecisiveness, and continuing confusion about the envoy's instructions" delayed Rassam's arrival at Tewodros's camp until January 1866. At first, it looked as if Rassam might succeed in the release of the hostages: the Emperor showed him great favour, establishing him at Qorata, a village on the south-eastern shores of Lake Tana, and sending him numerous gifts, and having Cameron, Stern, and the other hostages sent to his encampment.