Bleddyn is a masculine, Welsh given name.
Other spellings of Bleddyn are: Blevin, Blevyn, Blethyn, Blethin, Blevins, Blethins, Blethyns, Plethyn, Plethin, Pleddyn, Plethin and many others. People with the name include:
Bleddyn ap Cynfyn (died 1075), prince of the Welsh Kingdoms of Gwynedd and of Powys Bleddyn Bowen (born 1961), Welsh rugby player Bleddyn Fardd (1258–1284), Welsh-language court poet from Gwynedd Bleddyn Taylor (born 1959), Welsh rugby player Bleddyn Williams (1923–2009), Welsh rugby player Cadwgan ap Bleddyn (1051–1111), prince of Powys in eastern Wales Iorwerth ap Bleddyn (1053–1111), prince of Powys in eastern Wales Maredudd ap Bleddyn (1047–1132), prince of Powys in eastern Wales Rhiryd ap Bleddyn (1049–1088), Welsh king of Powys