De Morgan or de Morgan is a surname, and may refer to: Augustus De Morgan (1806–1871), British mathematician and logician Campbell De Morgan (1811–1876), British surgeon De Morgan's laws (or De Morgan's theorem), a set of rules from propositional logic The De Morgan Medal, a triennial mathematics prize awarded by the London Mathematical Society Evelyn De Morgan (1855–1919), English pre-Raphaelite painter Jacques de Morgan (1857–1924), French archaeologist Mary De Morgan (1850–1907), English author of literary fairytales William De Morgan (1839–1917), English designer, potter, ceramics-worker, and novelist