The first creations of Eru in J.R.R. Tolkien's Middle Earth mythology. In many ways, the Ainur share a parallel with the Angels of the Christian religion, including the similarity between the Ainur Melkor who was punished and cast down to Middle Earth where he became known as Morgoth (compare with Lucifer becoming Satan).

The Ainur are divided into two groups: the Valar, or greater Ainur, and the Maiar, or lesser Ainur.