Iolo is a diminutive of Iorwerth, a Welsh name. It may refer to:
- Iolo Goch (1320–1398), Welsh bard
- Iolo Morganwg (1747–1826), Welsh poet, antiquarian, and literary forger
- Iolo Ceredig Jones, Welsh chess player
- Iolo Williams, Welsh television presenter
- Iolo FitzOwen, character in the computer game series Ultima
