Kłosowski is Polish a surname. Notable people with the surname include:
George Chapman (murderer) (born Seweryn Kłosowski; 1865–1903), Polish serial killer Dolores Klosowski (1923–2016), All-American Girls Professional Baseball League player John Kloss (born John Klosowski; 1937–1987), American fashion designer Roman Kłosowski (1929–2018), Polish actor Sławomir Kłosowski (born 1964), Polish politician Theresa Klosowski, All-American Girls Professional Baseball League player
See also Klossowski (born Balthasar Klossowski de Rola; 1908–2001), Polish-French modern artist Klonowski, a surname