David McAdams Sibley Sr. (born 1947) is an oral and maxillofacial surgeon, attorney and lobbyist in Austin and Waco, Texas, who served from 1991 to 2002 as a Republican member of the Texas State Senate. Previously, he was from 1987 to 1988 the mayor of Waco, then an unelected and still a nonpartisan position, as are all elected municipal offices in Texas.