The Maiar are a fictional race from J. R. R. Tolkien's universe, Middle-earth.

The Maiar are those spirits which descended to Arda to help the Valar to shape the World. Singular is Maia. There were supposed to be numerous, yet not many were named.

Their chiefs are Eönwë, banner-bearer and herald of Manwë, and Ilmarë, the handmaid of Varda

Each of the Maiar was associated with one or more particular Vala, and were of similar stock, though less powerful. For example, Ossë and Uinen, as spirits of the sea, belonged to Ulmo, while Curumo, who came to be known in Middle-earth as Saruman, belonged to Aulë the Smith. Others included Sauron (originally also of Aulë's people), Aiwendil, who was known in Middle-Earth as Radagast the Brown and belonged to Yavanna, and Olórin, known as Gandalf, who belonged to Manwë and Varda. Alatar and Pallando, known as the Blue Wizards, travelled to the east, and never returned to the west. Their fate is unknown. The Balrogs, like Sauron, were Maiar corrupted by Melkor. Their associated Vala is not known. Melian served both Vana and Estë.