DeMars (and variants) is a surname. Notable people with the surname include:
AnnMaria De Mars (born 1958), American technology executive, author and Judoka
Billy DeMars (born 1925), American baseball shortstop and coach
Bruce DeMars (born 1935), United States Navy four star admiral
Hélène-Louise Demars (born c. 1736), French composer
Lina Van de Mars (born 1979), German TV moderator, motor athlete and drummer
Nicole Demars (born 1970), Canadian road cyclist
Vernon DeMars (1908-2005), American architect and professor
