Firby or Fritheby is an English toponymic surname, referring to the village of Firby south of Bedale, North Yorkshire, historically in the North Riding of Yorkshire. It is not to be confused with Firby near Malton, also now in North Yorkshire but historically in the East Riding of Yorkshire, which has different origins and etymology, or with Fearby or Ferriby (and their variants), also in Yorkshire but with different origins.