Vonnegut is the surname of:
Kurt Vonnegut (1922–2007), American science fiction writerClemens Vonnegut (1824–1906), German-American businessman, great-grandfather of Kurt VonnegutBernard Vonnegut I (1855–1908), American lecturer and architect, son of Clemens Vonnegut, Sr. and grandfather of KurtKurt Vonnegut, Sr. (1884–1957), American architect and lecturer, son of Bernard I and father of KurtBernard Vonnegut (1914–1997), American atmospheric scientist, elder brother of KurtEdith Vonnegut (born 1949), American painter, daughter of KurtMark Vonnegut (born 1947), American memoirist and journalist, son of KurtNorb Vonnegut (born 1958), American thriller author, fourth cousin of Kurt