Dain is a name for male people. Dáin or Dain can refer to:
- In Norse mythology:
- Dáin, a dwarf from Völuspá
- Dáinn, one of the four stags of Yggdrasill
- Dáinn, an elf who introduced the runes to his race according to Hávamál
- In J. R. R. Tolkien's Middle-earth legendarium:
- Dáin I, last King of the Dwarves in the Grey Mountains
- Dáin II Ironfoot, Dwarven King under the Lonely Mountain
- Dain (unit), an obsolete unit of measurement in Myanmar equalling ca 3.9 kilometres; see also Bamboo (unit)