Cossart is a surname. Notable people with the surname include:
Ernest Cossart (1876–1951), English actor Gabriel Cossart (1615–1674), French historian Hugh Cossart Baker Jr. (1846–1931), Canadian businessman Hugh Cossart Baker Sr. (1818–1859), Canadian banker Linda de Cossart, English surgeon Pascale Cossart (born 1948), French bacteriologist Yvonne Cossart (1934–2014), Australian virologist,