Katharine Wise Wintringham (10 February 1908 – 1966) was an American political activist, best known for her activities in the United Kingdom. Born Kitty Bowler in Plymouth, Massachusetts, Wintringham studied at Bryn Mawr College. There, she became involved in anti-fascist activity, joining the League Against War and Fascism and the International Labor Defense. After World War II, Kitty gave birth to a child, Benjamin, and focused on bringing him up. Tom died suddenly in 1949 and, a few years later, Kitty moved to Hawaii, but she later returned to the UK. She committed suicide in 1966.