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The Oregon boundary dispute or the Oregon Question, was a controversy over the political division of the Pacific Northwest of North America between several nations that had competing territorial and commercial aspirations over the region.

Expansionist competition into the region began in the 18th century, with participants including the Russian Empire, the United Kingdom of Great Britain and Ireland, the Kingdom of Spain and the United States of America. By the 1820s, both the Russians, through the Russo-American Treaty of 1824 and the Russo-British Treaty of 1825 and the Spanish, by the Adams Onis Treaty of 1819, formally withdrew their territorial claims in the region. Through these treaties the British and Americans gained residual territorial claims in the disputed area. The remaining portion of the North American Pacific coast contested by the United Kingdom and the United States was defined as the following: west of the Continental Divide of the Americas, north of Alta California at 42nd parallel north, and south of Russian America at parallel 54°40′ north; typically this region was referred to by the British as the Columbia District and the Oregon Country by the Americans. The Oregon Dispute began to become important in geopolitical diplomacy between the British Empire and the new American Republic, especially after the War of 1812.

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