Anjouan is an autonomous volcanic island in the Comoro Islands in the southwestern Indian Ocean, part of the Union of the Comoros. It is known in Shikomori as Ndzuani, Ndzuwani or Nzwani, and, until the early twentieth century when the name fell out of general use, in English as Johanna. Historically it was also called Hinzuan or Hanzoan.

The Comoro Islands or the Comoros are an archipelago of volcanic islands situated off the southeastern coast of Africa, to the east of Mozambique and northwest of Madagascar. The islands are politically divided between the Union of the Comoros, a sovereign country, and Mayotte, an Overseas Department of France.