Demšar is a surname. Notable people with the surname include:
Avgust Demšar (born 1962), Slovenian writer Danijel Demšar (born 1954), Slovenian illustrator and painter Franci Demšar (born 1960), Slovenian physicist and politician Janez Demšar (born 1951), Slovenian ski jumper Ladislav Demšar (1929–1992), Serbian basketball player and coach