Ascension Island is an island in the South Atlantic Ocean, a dependency of the British overseas territory of Saint Helena. Like other British territories, it issues its own postage stamps.

Originally mail was carried on an irregular basis as ships called. A datestamp was in use from February 1858, and in 1863 the Union Steamship Co. began regular carriage of mail, continuing until 1977. On 3 March, 1867 British postage stamps became valid for Ascension mail, and continued in use until 1922, when Ascension became a dependency of Saint Helena.

On 2 November 1922, nine stamps of St. Helena overprinted "ASCENSION" replaced British stamps. These were followed up in 1924 by a series of 12 using the St. Helena design, but inscribed for Ascension. In 1934 a pictorial series of ten engraved stamps depicted various views of the island.