John Sampson (1862 – 1931) was an Irish linguist. As a scholar he is best known for The Dialect of the Gypsies of Wales (1926), an authoritative grammar of the Welsh-Romany language. It was written with the collaboration of Edward Wood, who died in 1902. Sampson edited a collection the poetry of William Blake, Blake's "Poetical Works", that restored the text from original works and annotated the published variants; Alfred Kazin described this as "the first accurate and completely trustworthy edition'.
He was born in Schull, County Cork, Ireland, and had to leave school at the age of 14 after his father died. Sampson became librarian at University College, Liverpool in 1892, largely self-taught.
In 1901 he met the artist Augustus John, and they struck up a long friendship, leading to an emphasis in John’s works on Romany subjects.
Sampson's grandson, the writer Anthony Sampson, published a biography of him in 1997 entitled The Scholar Gypsy: The Quest For A Family Secret.