Merfyn ap Rhodri (died 900) was a late 9th century King of Powys.
Upon the death of his father, Rhodri the Great in 878, Merfyn inherited the Kingdom of Powys. Merfyn's 2 brothers Anarawd ap Rhodri, and Cadell ap Rhodri received the Kingdoms of Gwynedd and Seisyllwg.
| Preceded by Rhodri Mawr |
King of Powys 878–900 |
Succeeded by Llywelyn ap Merfyn |