Captain Iolo Aneurin Williams (18 June 1890 – 18 January 1962), was a British author, journalist and Liberal Party politician. His son was the composer Edward Williams.
Williams was born in Middlesbrough, the son of Aneurin Williams, who was a Liberal member of parliament. He was the brother of Ursula Williams who was also a Liberal politician. He was educated at Rugby School and King's College, Cambridge. In 1920 he married Francion Elinor Dixon. They had one son and two daughters.
Williams was Bibliographical Correspondent of the London Mercury from 1920–39. He made contributions to the Dictionary of National Biography, and the Cambridge Bibliography of English Literature. He was a published poet and author of the following works;
Williams was Liberal candidate for the Chelsea division of London at the 1924 General Election. Chelsea was a safe Unionist seat, so he was not expected to win. 1924 was not a good election for the Liberals and he duly came a poor third. Despite this, he contested Chelsea again at the 1929 General Election, a better election for the Liberals. He increased the Liberal share of the vote, but still finished third. He did not stand for parliament again.