Cassirer is a surname of Yiddish origin (קאַסירער kasirer, which means Cashier; Kassierer). Notable people with the surname include:

• Wilfred Cass, born Wolfgang Cassirer (1924–2022), German-Jewish founder of Cass Sculpture Foundation
• Bruno Cassirer (1872–1941), German-Jewish publisher and gallery owner in Berlin
• Ernst Cassirer (1874–1945), German-Jewish philosopher
• Fritz Cassirer (1871–1926), German-Jewish conductor
• Heinz Cassirer (1903–1979), German-German philosopher
• Julius Cassirer (1841–1924), German-Jewish industrialist and art collector
• Paul Cassirer (1871–1926), German-Jewish art dealer and editor
• Richard Cassirer (1868–1925), German-Jewish neurologist

• Jerome P. Kassirer (born 1932), American nephrologist

• History of the Cassirer family