Johnsen is a patronymic surname meaning "son of John". Notable people with the surname include:
Arne Odd Johnsen (1909–1985), Norwegian medieval and economic historianArve Johnsen (born 1934), Norwegian industrial executive and politicianBent Inge Johnsen, Norwegian football (soccer) playerBjarne Johnsen (1892–1984), Norwegian gymnast, 1912 Summer OlympicsBritton Johnsen (born 1979), American professional basketball playerDawn Johnsen, American lawyerEgil Børre Johnsen, Norwegian writerErik Johnsen (born 1965), Norwegian Ski jumperErland Johnsen (born 1967), Norwegian football coach; former playerEspen Johnsen (born 1979), Norwegian football goalkeeper; brother of football defender MariusEspen Johnsen (politician) (born 1976), Norwegian Member of Parliament for OpplandFrode Johnsen (born 1974), Norwegian player of the Japanese football club Nagoya Grampus EightGörel Johnsen (born 1949), ABBA’s personal managerGrethe Gynnild Johnsen, Norwegian journalistHans Johnsen, American Medal of Honor recipientHarvey M. Johnsen, American federal judgeHåkon Johnsen (1914–1991), Norwegian politician for the Norwegian Labour PartyJarl Johnsen (1913–1986), Norwegian boxerJennie Johnsen (born 1977), Norwegian politician for the Liberal PartyJohan Christian Johnsen (1815–1898), Norwegian politicianJohn Johnsen (1892–1984), Norwegian freestyle and backstroke swimmerJustin Meldal-Johnsen (born 1970), bassist with BeckKetil Melsted Johnsen Motzfeldt (1814–1889), Norwegian Minister of the Navy and Minister of Postal AffairsLinda Johnsen (born 1954), American author on yoga and HinduismMarius Johnsen (born 1981), Norwegian football defender; brother of goalkeeper EspenMark R. Johnsen, American brewerMichael Johnsen, Australian politicianOlaus Johnsen, World War I flying acePål Johnsen, Norwegian hockey playerPer Johnsen, Norwegian sprint canoeistPeter Johnsen, American educator, Provost at Bradley UniversityRobert Johnsen (1896–1975), Danish gymnast, 1920 Summer OlympicsRonny Johnsen (born 1969), Norwegian football playerSigbjørn Johnsen (born 1950), Norwegian politician for the Norwegian Labour PartySteinar Sverd Johnsen, Norwegian musician and composerTheo A. Johnsen (1857–1911) American manufacturer of ski equipmentTor Gunnar Johnsen, Norwegian football forwardTorhild Johnsen, Norwegian politician for the Christian Democratic PartyVibeke Johnsen, Norwegian team handball playerWayne Johnsen (born 1977), American boxer