Niall \ni(a)-ll\ as a boy's name is pronounced NYE-al, NEE-al. It is of Irish and Gaelic origin, and the meaning of Niall is "champion". Source form of Neil, used mainly in Ireland. Historical: Niall of the Nine Hostages founded a dynasty of Irish kings. See also Nigel, Niles, and Nyles.
Niall has 1 variant form: Nial.