John Dillwyn Llewelyn (1810–1882), Welsh botanist and pioneer photographer
•
John Anthony Llewellyn (1933–2013), British-born American scientist and NASA astronaut
•
Sir John Dillwyn-Llewellyn, 1st Baronet (1836–1927), Welsh Conservative Member of Parliament
John F. Kennedy | Pope John Paul II | Elton John | John | John Lennon | John Wayne | John McCain | John Kerry | John Cage | Olivia Newton-John | John Williams | John Peel | John Adams | John Steinbeck | John Travolta | John Milton | John Zorn | John Marshall | John Howard | John Singer Sargent | John Ruskin | John Updike | John Maynard Keynes | John Coltrane | John Cleese | St. John's | John Waters | John Lee Hooker | John Huston | John Ford |
On 17 October 1929 he married Elizabeth Nance Llewellyn, daughter of Owen John Llewellyn of Moulsford, Berkshire (now Oxfordshire).