Niall is a male given name of Gaelic origin, thought to mean "champion". It could also mean "cloud" or "passionate".
Notable people with the name Niall
- Medieval times
- Niall of the Nine Hostages, High King of Ireland who lived in the early-to-mid 5th century AD
- Niall Caille mac Áeda, High King of Ireland in the 9th century AD
- Modern times
- Niall Ferguson (b. 1964), Historian and the Laurence A. Tisch Professor of History at Harvard University
- Niall Horan (b. 1993), a member of the boy band One Direction
- Niall O'Brien (b. 1981), Irish cricketer
- Niall Quinn (b. 1966), Irish former international footballer and chairman of the English club Sunderland A.F.C.
- List of Irish-language given names