David Vernon Widder (25 March 1898 – 8 July 1990) was an American mathematician. He earned his Ph.D. at Harvard University in 1924 under George Birkhoff and went on to join the faculty there. He was a co-founder of the Duke Mathematical Journal and the author of the textbook Advanced Calculus (Prentice-Hall, 1947). He wrote also The Laplace transform (in which he gave a first solution to Landau's problem on the Dirichlet eta function), An introduction to transform theory, and The convolution transform (co-author with I. I. Hirschman).