In the fictional universe of J. R. R. Tolkien, Ar-Adûnakhôr was the 20th ruler of Númenor. He opposed the Valar, and thus took his name in the Adûnaic language instead of using the traditional Elvish language form (Tar-Herunumen).

There is some question as to whether Ar-Adûnakhôr succeded his father, Tar-Ardamin, as King, or his grandfather, Tar-Calmacil, but the numbering of the rulers includes Tar-Ardamin in the count.

He was succeeded by his son, Ar-Zimrathôn.

Preceded by:
Tar-Ardamin
List of rulers of Númenor Succeeded by:
Ar-Zimrathôn