Flagstad is a Norwegian surname. Notable people with the surname include:
Karen-Marie Flagstad (1904–1992), Norwegian opera singer, daughter of Maja and Michael, sister of Kirsten Kirsten Flagstad (1895–1962), Norwegian opera singer Maja Flagstad (1871–1958), Norwegian pianist Michael Flagstad (1869–1930), Norwegian musician and conductor Mikkel Flagstad (1930–2005), Norwegian jazz musician, grandson of Maja and Michael
See also Fløgstad