Milton Stanley Livingston was an American accelerator physicist, co-inventor of the cyclotron with Ernest Lawrence, and co-discoverer with Ernest Courant and Hartland Snyder of the strong focusing principle, which allowed development of modern large-scale particle accelerators. He built cyclotrons at the University of California, Cornell University and the Massachusetts Institute of Technology. During World War II, he served in the operations research group at the Office of Naval Research.

A cyclotron is a type of particle accelerator invented by Ernest Lawrence in 1929–1930 at the University of California, Berkeley, and patented in 1932. A cyclotron accelerates charged particles outwards from the center of a flat cylindrical vacuum chamber along a spiral path. The particles are held to a spiral trajectory by a static magnetic field and accelerated by a rapidly varying electric field. Lawrence was awarded the 1939 Nobel Prize in Physics for this invention.