Flatt is a surname, and may refer to:
Bruce Flatt (born 1965), Canadian businessman Ernie Flatt (1918–1995), American choreographer and dancer Johann Friedrich Flatt (1759–1821), German theologian and philosopher John Ira Flatt (1834–1913), Canadian farmer, merchant and politician Jonathan Flatt (born 1994), English footballer Lester Flatt (1914–1979), American bluegrass musician, guitarist and mandolinist Matthew Flatt, American computer scientist Rachael Flatt (born 1992), American figure skater Roy Flatt (1947–2011), English clergyman
See also Flatt (landform), a heathland pond, typical of North Germany