Ainu or Aynu may refer to:
- Ainu people, an East Asian ethnic group of Japan and the Russian Far East
- Ainu languages, a family of languages
- Ainu language of Hokkaido
- Kuril Ainu language, extinct language of the Kuril Islands
- Sakhalin Ainu language, extinct language from the island of Sakhalin
- Ainu music
- Ainu cuisine
- Ainu (Middle-earth), spirit in J. R. R. Tolkien's legendarium
- Ainu (insect), a beetle in the family Tenebrionidae
- Äynu people, of Western China
- Äynu language
See also
- Äynu (disambiguation)
- Ainur (disambiguation)
- Aino (disambiguation)
- Aniu, character from Balto II