Amakusa (天草; Japanese pronunciation: [a.maꜜ.kɯ̥.sa]) is a series of islands off the west coast of Kyushu, the southernmost of the four main islands of Japan.

The largest island of the Amakusa group is Shimoshima, which is 26.5 miles long and 13.5 miles at its widest (42.6 km × 21.7 km). It is situated at 32°20'N, 130°E, separated from the rest of Kumamoto Prefecture by the Yatsushiro Sea.

While lacking high mountains with only four peaks surpassing 1,500 feet (460 m), the island terrain is ruggedly hilly. To cope with the lack of flat arable land, farming is carried out on a terrace system of cultivation.^{[citation needed]}

Amakusa, along with the neighboring Shimabara Peninsula, became the site of the Shimabara rebellion in the 17th century, led by Christians. Following the rebellion, Kakure Kirishitan, the Christians who had survived, continued to practice their faith in secret, despite severe persecution.

Amakusa produces a little coal and pottery stone, both being used by the potters of Hirado ware and Satsuma ware. Many kilns remain on the islands today, and pottery and pottery stone are still exported.

Amakusa pottery has been recognised by the government. The retail company Muji brought out its own line of Hakuji home ware, which is produced out of ground translucent Amakusa stones kneaded into clay, using traditional techniques.

Hidenoshin Koyama, who built Thomas Blake Glover's House in Glover Garden, came from this island.

Kenta and Ko-shin, two of the three members of Wanima come from the island of Amakusa.