Iolo is a diminutive of Iorwerth, a Welsh name. It may refer to:
Iolo Goch (1320–1398), Welsh bard Iolo Ceredig Jones (1947–2021), Welsh chess player Iolo Morganwg (1747–1826), Welsh poet, antiquarian, and literary forger Iolo Aneurin Williams (1890–1962), British writer, journalist and Liberal Party politician Iolo Williams (born 1962), Welsh television presenter
See also Iolo FitzOwen, character in the computer game series Ultima