McAdam or MacAdam is a Scottish Gaelic clan which originated as a branch of Clan Gregor. As a surname it is most prominent in the Galloway and Ayrshire regions of Scotland. Some of their descendants are also to be found in Ireland, the United States, Australia and Canada. Notable people with the surname include:
Adrian McAdam (born 1971), Australian Rules footballer
Colin McAdam (novelist), a Canadian novelist
David MacAdam (1910-1998), an American color scientist
Doug McAdam (born 1951), an American sociologist studying social movements
Elliot McAdam (born 1951), an Australian politician and Northern Territory Cabinet member
Gilbert McAdam (born 1967), Australian Rules footballer
Greg McAdam (born 1961), Australian Rules footballer
John Loudon McAdam (1756-1836), a Scottish engineer noted for inventing the process of "macadamization" of roads.
John McAdam (businessman), an American businessman
John McAdam (politician) (1807-1893), Irish-born politician in New Brunswick, Canada
John Macadam (1827-1865), an Australian (Scottish-born) chemist, medical teacher and politician, after whom the Macadamia nut is named
Keith McAdam, Scottish cricketer and specialist in tropical diseases
Macadam, a British illustrator active during the 1920s and 1930s
Patrick "Pat" MacAdam is a Canadian writer
Sean McAdam, an American baseball writer
