Carstensen is a patronymic surname. Notable people with the surname include:
Andreas Riis Carstensen (1844–1906), Danish painter
Bianca Carstensen (born 1975), Danish rower
Carl Carstensen (1863–1940), Danish Scouting pioneer
Christian Carstensen (born 1973), German politician
Dee Carstensen (born 1956), American singer-songwriter and harpist
Ebba Carstensen (1885–1967), Danish painter
Fritze Carstensen (1925–2005), Danish swimmer
Georg Carstensen (1812–1857), Danish military officer and developer of Tivoli Gardens Hans Jacob Carstensen (born 1965), Danish businessman Henrik Carstensen (1753–1835), Norwegian businessman, timber merchant and shipowner Jacob Carstensen (born 1978), Danish swimmer Johannes Carstensen (1924—2010), Danish painter Kira Carstensen, documentary filmmaker Laura L. Carstensen, American psychologist Margit Carstensen (1940–2023), German actress Peter Harry Carstensen (born 1947), German politician Povl Erik Carstensen (born 1960), Danish comedian, actor and jazz double bassist Stian Carstensen (born 1971), Norwegian musician Tage Carstensen, Danish Scouting pioneer