Y Gododdin is a medieval Welsh poem consisting of a series of elegies to the men of the Brittonic kingdom of Gododdin and its allies who, according to the conventional interpretation, died fighting the Angles of Deira and Bernicia at a place named Catraeth in about AD 600. It is traditionally ascribed to the bard Aneirin and survives only in one manuscript, the "Book of Aneirin".

The Gododdin were a Brittonic people of north-eastern Britannia, the area known as the Hen Ogledd or Old North, in the sub-Roman period. Descendants of the Votadini, they are best known as the subject of the 6th-century Welsh poem Y Gododdin, which memorialises the Battle of Catraeth and is attributed to Aneirin.