Søby is a Danish surname. Notable people with the surname include:
Egil Søby (born 1945), Norwegian sprint canoeist
Frode Søby (born 1935), Danish chess master
Nina Søby (born 1956), Norwegian former professional racing cyclist
Søs Søby (born 1991), Danish handballer
Tove Søby (born 1933), Danish sprint canoer