Mark Waldo Zemansky (May 5, 1900 – December 29, 1981) was an American physicist. He was a professor of physics at the City College of New York for decades and is best known for co-authoring University Physics, an introductory physics textbook, with Francis Sears. The book, first published in 1949, is often referred to as "Sears and Zemansky", although Hugh Young became a coauthor in 1973.