Æthelfrith (disambiguation)
Æthelfrith (d. c. 616) was King of Bernicia and Deira in northern England.
Æthelfrith or Aethelfrith may also refer to:
- Æthelfrith of Elmham (d. c. 745), Bishop of Elmham
- Æthelfrith of Mercia (fl. 883 – 915), Ealdorman in Mercia