Sundby may refer to: __NOTOC__ Places Denmark Sundby, Copenhagen, a district in Copenhagen Sundby, Lolland, a satellite town of Nykøbing Falster on Lolland Nørresundby, a town on North Jutlandic Island
Sweden Sundby, Sweden, a locality on Ekerö in Stockholm County Sundbyberg Municipality, Sweden
People with the surname Martin Johnsrud Sundby, Norwegian cross-country skier Ragnhild Sundby (1922–2006), Norwegian zoologist