Westermann is a surname meaning "man from the West". Notable people with the surname include:
Antoine Westermann (born 1946), French chefBernt Wilhelm Westermann (1781-1868), Danish businessman and entomologistChristine Westermann (born 1948), radio and TV hostClaus Westermann (1909–2000), German protestant theologianDiedrich Westermann (1875–1956), German missionary, ethnographer and African linguistFrançois Joseph Westermann (1751-1794), Alsace-born French general and political figure of the French RevolutionGeorge Westermann (1810–1879), German publisherGerhard Westermann (1880-1971), Dutch artistH. C. Westermann (1922–1981), American sculptorHans Westermann (1890–1935), German communist politician (KPD) and member of the resistanceHeiko Westermann (born 1983), German football playerLéo Westermann (born 1992), French basketball playerLiesel Westermann (born 1944), German athleteWilliam Linn Westermann (1873–1954), American historian