Dagg is a surname. Notable people with the surname include:

  • Anne Innis Dagg (born 1933), Canadian zoologist, feminist and author
  • Archie Dagg, traditional fiddler, piper and composer from Northumberland
  • Israel Dagg (born 1988), New Zealand international rugby union player
  • John L. Dagg (1794–1884), American Baptist minister and theologian
  • Lyall Dagg, Canadian curler