William Prager (May 23, 1903, Karlsruhe - 1980) was a German-born US applied mathematician.
He was a lecturer at Darmstadt, a deputy director at University of Göttingen, professor at Karlsruhe, University of Istanbul, the University of California, San Diego and Brown University, where he advised Bernard Budiansky.
The Society of Engineering Science has awarded the Wiliam Prager Medal in Solid Mechanics since 1983 in his honor.[1]