Wilfrid Meynell (17 November 1852, Newcastle-upon-Tyne – 20 October 1948, PulboroughObituary, The Times, 22 October 1948), who sometimes wrote under the pseudonym John Oldcastle, was a British newspaper publisher and editor.

Born of an old Yorkshire family on his father's side, he was related to a family of distinguished Quakers on his mother's side: his grandfather was Samuel Tuke, and James Hack Tuke and Daniel Hack Tuke were uncles.

In 1870, aged 18, Meynell became a convert to Roman Catholicism. He married the writer Alice Thompson in 1877.The pair's first effort at periodical publishing was The Pen, a short-lived critical monthly review. In 1881 he accepted Cardinal Manning's invitation to edit the Catholic Weekly Register, and continued to do so until 1899. Meynell later founded and edited (1883-94) the magazine Merry England, in which he discovered and sponsored the poet Francis Thompson.

Meynell wrote biographies of Manning, John Henry Newman and Pope Leo XIII. He contributed to a wide range of periodicals including the Contemporary Review, The Art Journal, the Magazine of Art, the Athenaeum, the Academy, the Saturday Review, the Pall Mall Budget, the Illustrated London News, the Daily Chronicle and the Nineteenth Century. During March 1906, The Windsor Magazine published an article entitled Politics - Second Series that was coauthored by Meynell and Bertram Fletcher Robinson. This article was recently republished in a book entitled The World of Vanity Fair that was edited by Paul Spiring (see ).

By the 1920s, Meynell principally wrote for the Dublin Review and the Tablet.
Wilfrid and Alice Meynell had nine children, including the founder of The Nonesuch Press, Francis Meynell.