The Lay of Aotrou and Itroun is a poem of 508 lines, written by J. R. R. Tolkien in 1930 and published in Welsh Review in December 1945.

The poem is modelled on the genre of the "Breton lay" popular in Middle English literature of the 12th century, and it explores the conflict of heroic or chivalric values and Christianity, and their relation to the institution of marriage.

[1] Tolkien adds to his source a stern moral – repudiation of all traffic with the supernatural and the occult.

When Itroun is with child, the witch reappears, revealing herself as the Corrigan, and asks for Aotrou's love as payment.

They are buried together, and they do not live to see their offspring grow up – something that has been interpreted as a judgement on Aotrou for excessive family pride.