The Andreanof Islands are a group of islands in the Aleutian Islands in southwest Alaska between the Rat Islands group, to the west and the Fox Islands group, to the east, at about 52° North and 172°57' to 179°09' West. The islands extend about 440 km (275 miles).

The largest islands in the group, from west to east, Gorelei, Amatigras, Tanaga, Kanaga, Adak, Tagalak, Great Sitkin, Atka, Amlia and Seguyam.

The islands are usually foggy and are treeless because of the almost constant wind. They were named for the Russian navigator, Andreian Tolstyk, who was the first to explore the islands in 1761.

There were several United States military bases on the islands during World War II. The bases on Adak were enlarged and made permanent after the war but were closed in 1995.