Dementyev, often spelt Dementiev (feminine: Dementyeva), is a Russian surname that is derived from the male given name Dementiy and literally means Dementiy's. Notable people with the surname include:
Dementyev Andrey Dementyev (disambiguation), multiple people Carolina Dementiev (born 1989), Panamanian model Georgi Petrovich Dementiev (usual spelling) (1898–1969), Russian ornithologist Nikolay Dementyev (footballer, born 1915) (1915–1994), Soviet football player and coach Oleg Dementiev (1938–1991), Russian chess master Peter Demens, born Pyotr Alexeyevitch Dementyev (1850–1919), Russian immigrant, railway owner and one of the founders of the U.S. city of St. Petersburg, Florida Pyotr Dementyev (1913–1998), Soviet football player and coach, brother of Nikolay Yevgeny Dementyev (born 1983), Russian cross-country skier
Dementyeva Elena Dementieva (born 1981), Russian tennis player Yelizaveta Dementyeva (1928–2022), Russian sprint canoer Anna Dementyeva (born 1994), Russian artistic gymnast