Lalor is an Irish surname derived from the Gaelic O Leathlobhair, meaning Half Leper. This is also the origin or the other variations in spelling of the name, O'Lawlor, Lawlor and Lawler. It is most commonly found around the midlands of Ireland especially County Laois, being one of the Seven Septs (Clans) of Leix (O'Lalors, O'Moores, O'Dowlings, O'Dorans, O'Devoys, O'Kellys, and McEvoys). It is not, as some people have claimed, of Norse origin. It can also refer to:
- Denis Lalor, athlete
- Francis Ramsey Lalor (1856–1929), politician
- John Lalor (1814–1856), journalist and author
- James Fintan Lalor, Irish rebel
- Kieran Lalor, politician
- Mike Lalor (born 1963), ice hockey player
- Patrick Lalor (born 1926), politician
- Peter Lalor, the leader of the Eureka Stockade rebellion
- Richard Lalor (1823–1893), politician
- Richard Lalor Sheil (1791–1851), politician, writer and orator
- Teresa Lalor (?-1846), nun
- Patrick "Patt" Lalor (1781-1856), Irish national politician