Llywelyn ap Maredudd (died 1263) was a minor Welsh prince of the House of Gwynedd who was the last vassal Lord of Meirionydd. He lived during the mid 13th century. He was the son of Maredudd ap Llywelyn ap Maredudd ap Cynan and was a direct descendant of Owain Gwynedd through his son Prince Cynan, Lord of Meirionydd. Llywelyn ap Maredudd was a distant cousin and contemporary of Llywelyn ap Gruffudd the last native Prince of Wales and is known to have had the following sons;
- Madog ap Llywelyn ap Maredudd
- Dafydd ap Llywelyn ap Maredudd
- Llywelyn ap Llywelyn ap Maredudd
- Maredudd ap Llywelyn ap Maredudd
His eldest son, Madog, led an uprising against English occupation between 1294-1295. He was survived by two sons whose fates are as yet unknown. The descendants of these children, as well as those of Madog's younger brothers Dafydd, Llywelyn and Maredudd represent potential extant branches of the House of Gwynedd.