Giselher, Gisilher, Gisiler, or Giseler (Latin: Gislaharius) is a Germanic masculine given name. It may refer to:
Giselher of Burgundy, Burgundian king
Gisilher (archbishop of Magdeburg) (died 1004), German ecclesiastic
Giselher Klebe (1925–2009), German composer
Giselher Schubert (born 1944), German musicologist
Giselher Wilke (1922–2007), German army officer
Giselher Wirsing (1907–1975), right-wing German journalist, author, and foreign policy expert