Koslowski is a surname. It is a variant of Kozłowski. Notable people with the surname include:
Álvaro Koslowski (born 1971), Brazilian sprint canoer Dennis Koslowski (born 1959), American Olympic wrestler Duane Koslowski (1959–2025), American Olympic wrestler, twin brother of Dennis George Bernard "Dave" Koslowski (1920–1975), American baseball player Peter Koslowski (1952–2012), German professor of philosophy Willi Koslowski (1937–2024), German football player
See also Kozłowski, a surname Kozlovsky, a surname