- The name Ethelred is composed from Old English elements æðele, meaning "noble", and ræd, meaning "counsel", being bombastic and common in the Royal House of Wessex.
- King Ethelred II of England was known as the Unready after his death (from Old English Æþelræd Unræd). In that time, "unready" was probably understood pejorative as "evil counsel" (opposite to the name) or "bad plan"; the king was considered ill-advised or indecisive in his conflict with the Danes.
- Harry Potter and the Philosopher's Stone (video game) (Appears on a Famous Wizard Card)
- Harry Potter and the Chamber of Secrets (video game) (Appears on a Famous Wizard Card)
- Harry Potter and the Prisoner of Azkaban (video game)(Appears on a Famous Wizard Card)