Francis Weston Sears (October 1, 1898 – November 12, 1975) was an American physicist.
He was a professor of physics at MIT for 35 years before moving to Dartmouth College in 1956 and is best known for co-authoring University Physics, an introductory physics textbook, with Mark Zemansky.
The book, first published in 1949, is often referred to as "Sears and Zemansky", although Hugh Young became a coauthor in 1973.
In 1932 he collaborated with Peter Debye in the discovery of what is now called the Debye-Sears effect, the diffraction of light by ultrasonic waves.Sears was a Fellow of the Optical Society of America, and was active in the American Association of Physics Teachers, serving as its president in 1956.