William Allingham (19 March 1824 – 18 November 1889) was an Irish poet, diarist and editor.
He wrote several volumes of lyric verse, and his poem 'The Faeries' was much anthologised; but he is better known for his posthumously published Diary, in which he records his lively encounters with Tennyson, Carlyle and other writers and artists.
His wife, Helen Allingham, was a well-known watercolourist and illustrator.