Johnsen is a patronymic surname meaning "son of John". Notable people with the surname include:
Arne Odd Johnsen (1909–1985), Norwegian medieval and economic historian
Arve Johnsen (born 1934), Norwegian industrial executive and politician
Bent Inge Johnsen, Norwegian football (soccer) player
Bjarne Johnsen (1892–1984), Norwegian gymnast, 1912 Summer Olympics
Britton Johnsen (born 1979), American professional basketball player
Dawn Johnsen, American lawyer
Egil Børre Johnsen, Norwegian writer
Erik Johnsen (born 1965), Norwegian Ski jumper
Erland Johnsen (born 1967), Norwegian football coach; former player
Espen Johnsen (born 1979), Norwegian football goalkeeper; brother of football defender Marius
Espen Johnsen (politician) (born 1976), Norwegian Member of Parliament for Oppland
Frode Johnsen (born 1974), Norwegian player of the Japanese football club Nagoya Grampus Eight
Görel Johnsen (born 1949), ABBA’s personal manager
Grethe Gynnild Johnsen, Norwegian journalist
Hans Johnsen, American Medal of Honor recipient
Harvey M. Johnsen, American federal judge
Håkon Johnsen (1914–1991), Norwegian politician for the Norwegian Labour Party
Jarl Johnsen (1913–1986), Norwegian boxer
Jennie Johnsen (born 1977), Norwegian politician for the Liberal Party
Johan Christian Johnsen (1815–1898), Norwegian politician
John Johnsen (1892–1984), Norwegian freestyle and backstroke swimmer
Justin Meldal-Johnsen (born 1970), bassist with Beck
Ketil Melsted Johnsen Motzfeldt (1814–1889), Norwegian Minister of the Navy and Minister of Postal Affairs
Linda Johnsen (born 1954), American author on yoga and Hinduism
Marius Johnsen (born 1981), Norwegian football defender; brother of goalkeeper Espen
Mark R. Johnsen, American brewer
Michael Johnsen, Australian politician
Olaus Johnsen, World War I flying ace
Pål Johnsen, Norwegian hockey player
Per Johnsen, Norwegian sprint canoeist
Peter Johnsen, American educator, Provost at Bradley University
Robert Johnsen (1896–1975), Danish gymnast, 1920 Summer Olympics
Ronny Johnsen (born 1969), Norwegian football player
Sigbjørn Johnsen (born 1950), Norwegian politician for the Norwegian Labour Party
Steinar Sverd Johnsen, Norwegian musician and composer
Theo A. Johnsen (1857–1911) American manufacturer of ski equipment
Tor Gunnar Johnsen, Norwegian football forward
Torhild Johnsen, Norwegian politician for the Christian Democratic Party
Vibeke Johnsen, Norwegian team handball player
Wayne Johnsen (born 1977), American boxer
