"Eliduc" is a Breton lai by the medieval poet Marie de France. The twelfth and last poem in the collection known as The Lais of Marie de France, it appears in the manuscript Harley 978 at the British Library. Like the other poems in this collection, "Eliduc" is written in the Anglo-Norman dialect of Old French, in couplets of eight syllables in length. At 1184 lines, it is the longest of the lais attributed to Marie de France. The text of the lai notes that its correct title should be Guildeluec and Guilliadon, but the name Eliduc has stuck.