Nils Christensen or Kristensen may refer to:

• Nils Christensen (aviator) (1921–2017), Norwegian-Canadian aviator
• Nils Christensen Ringnæs (1792–1863), Norwegian politician
• Nils Reinhardt Christensen (1919–1990), Norwegian film director and screenwriter
• Nils Christiansen (1913–1988), Filipino swimmer
• Niels Christiansen (born 1966), Danish businessman, CEO of Lego
• Niels Christensen (1865–1952), Danish-American inventor
• Niels Christian Christensen, (1881–1945), Danish sport shooter
• Niels Kristensen (born 1988), Danish football midfielder
• Niels Kristensen (rower) (born 1920), Danish rower