Seyfarth is a German language surname that stems from the male given name Siegfried. Notable people with the name include:
Alex Seyfarth (born 1999), Australian professional rugby league footballer Andreas Seyfarth (born 1962), German-style board game designer Juliane Seyfarth (born 1990), German ski jumper Jürgen Seyfarth (fl. 1981–1983), German rower Robert Seyfarth (scientist) (born 1948), American primatologist and author Robert Seyfarth (1878–1950), American architect