Mårtensson, Mårtenson and Martenson are surnames. Notable people with the names include:
Agneta Mårtensson (born 1961), Swedish freestyle swimmer
Anders Mårtensson (1893–1973), Swedish vaulter who competed in the 1920 Summer Olympics
Bertil Mårtensson (born 1945), Swedish author of science fiction, crime fiction and fantasy; also an academic philosopher
Bodil Mårtensson (born 1952), Swedish author of crime (police) novels and adventure books
Christopher Martenson (born 1962), American writer and trend forecaster
Frithiof Mårtensson (1884–1956), Swedish wrestler who competed in the 1908 Summer Olympics
Jan Mårtenson (born 1933), Swedish diplomat and writer of crime novels
Jörgen Mårtensson (born 1959), Swedish orienteer
Johan Mårtensson (born 1989), Swedish football player, who plays midfielder for FC Utrecht
Lasse Mårtenson (born 1934), Finnish singer
Mona Mårtenson (1902–1956), Swedish actress
Stina Mårtensson (1882–1962), Swedish missionary
Tony Mårtensson (born 1980), professional Swedish ice hockey center