Nilsen is a surname of Norwegian origin, meaning "son of Nils". It refers to:
Adolf Nilsen (1895–1927), Norwegian Olympic rowerAlfred Nilsen (1892–1977), Norwegian politician; served one term in the Storting 1950–54Alfred Sigurd Nilsen (1891–1977), Norwegian politician; served three terms in the StortingAnders Nilsen (disambiguation), several peopleArne Nilsen (born 1924), Norwegian government ministerB. J. Nilsen (born 1975), Swedish sound artistBetty Ann Bjerkreim Nilsen (born 1986), Norwegian orienteering competitor and cross country skierDennis Nilsen (born 1945), Scottish serial killerEinar Nilsen (1901–1980), Norwegian Olympic boxerElin Nilsen (born 1968), Norwegian Olympic skierErling Nilsen (1910–1984), Norwegian Olympic boxerHarald Christian Strand Nilsen (born 1971), Norwegian Olympic skierIda Nilsen (contemporary), Canadian singer and songwriterJeanette Nilsen (born 1972), Norwegian Olympic handball playerJimmy Nilsen (born 1966), Swedish motorcycle speedway riderKristoffer Nilsen (1901–1975), Norwegian Olympic boxerKurt Nilsen (born 1978), Norwegian pop/country singerLaila Schou Nilsen (1919–1998), Norwegian Olympic skater and skierLars Arvid Nilsen (born 1965), Norwegian shot putterLillebjørn Nilsen (born 1950), Norwegian singer, songwriter, and folk musicianNils Emaus Nilsen (1886–1976), Norwegian politician; Served one term in the Storting 1950–54Oddvard Nilsen (born 1940), Norwegian politician, served three terms in the StortingOlav Nilsen (born 1942), Norwegian professional football playerOle-Jørgen Nilsen (1936–2008), Norwegian actorOliver John Nilsen (1884–1977), Australian businessman and Lord Mayor of MelbournePeder Nilsen (1846–1921), Norwegian government ministerPhil Nilsen (born 1985), English rugby union football playerRoger Nilsen (born 1969), Norwegian professional football playerRudolf Nilsen (1901–1929), Norwegian poet and journalistRune Nilsen (1923–1998), Norwegian Olympic triple jumperSelmer Nilsen (1931–1991), Norwegian fisherman who spied for KGB during the Cold WarSpencer Nilsen (born 1961), American video game music composerSteinar Nilsen (born 1972), Norwegian professional football player and managerTom-Christer Nilsen (born 1969), Norwegian politician from HordalandTorstein Aagaard-Nilsen (born 1964), Norwegian music composerWerner Nilsen (1904–1992), Norwegian-American soccer player