Mạc (chữ Hán: 莫) is a Vietnamese surname. The name is transliterated as Mo in Chinese and Mua in Hmong language. It is also of Gaelic origin, meaning son, used as a prefix in many Irish and Scottish surnames e.g. MacDonald, and MacGregor.
Mac is the anglicised variation of the surname Mạc.
As a surname, Mac is the 409th most common surname, in Great Britain, with 23,149 bearers. It is most common in the Aberdeen City council area, and Greater Manchester, where it is the 25th and 107th most common surname, in both counties having 3,268 bearers, respectively. Other concentrations include, the Western Isles, (13th,1,712), East Lothian, (63rd,1,698), the Glasgow City council area, (90th,3,188), County Down, (147th,1,686), East Sussex, (247th,1,646), Belfast, (266th,1,682), Berkshire, (383rd,1,696), South Yorkshire, (466th,1,626), Merseyside, (490th,1,624), and Greater London, (1,189th,1,730).