Auxiliaries or Auxilia may refer too:
- Imperial Auxiliaries, units of the Imperial Army that where raised on the homeworld of Space Marines Legions during the Great Crusade
- Imperialis Auxilia, the name for the Imperial Army in High Gothic
- Gue'vesa Auxiliaries
- Solar Auxilia
- Tau Auxiliaries
- Terranic Auxilia
- Ultramar Auxilia