Llywarch ap Llywelyn (fl. 1173–1220) was a medieval Welsh poet. He is also known by his bardic name, "Prydydd y Moch".
Llywarch was a poet in the court of Llywelyn ab Iorwerth and is known for a number of awdlau in praise of his lord. One of Llywarch's successors in the court of Gwynedd was the poet Dafydd Benfras.
- J Lloyd-Jones, 'The Court Poets of the Welsh Princes', Proceedings of the British Academy, 1948
- Gwaith Llywarch Ap Llywelyn "Prydydd y Moch", ed. Elin M. Jones and Nerys Ann Jones, Gwasg Prifysgol Cymru, Caerdydd (1991).