William Dudley "Dud" Lastrapes, Jr. (born November 30, 1929), is a Lafayette, businessman, who was the first Republican since Reconstruction to have been elected mayor of his city, the fourth largest in Louisiana, according to the 2000 census. Lastrapes (pronounced LA STRAPS) was mayor for three terms, having served from from 1980-1992. Previously, he was a member of the Lafayette Parish School Board from 1972-1980. After his mayoral service, Lastrapes served a two-year term as chairman of the Louisiana Republican Party from 1992-1994. He has been a member of the Louisiana Gaming Control Board, under appointment of former Republican Governor Murphy J. "Mike" Foster, Jr., since 1997. The term expires at the end of 2008; he is ineligible to be reappointed.

Lastrapes was originally a Democrat, but he switched his registration to Republican in 1959, when he was not quite thirty years of age. At the time, the state Republican Party had fewer than nine thousand registered members. Hence very few living Louisiana Republicans have been members of the party longer than Lastrapes.