Richard Posthumus (born 19 July 1950), American politician, is a former State Senate Majority leader and Republican gubernatorial candidate from Michigan.

Dick Posthumus grew up in Alto, Michigan outside of Grand Rapids. He attended Michigan State University and was chair of the College Republicans. In 1971 he successfully ran the State House campaign of fellow student and future Michigan governor John Engler. He went on to serve in the State Senate eventually becoming Senate Majority Leader and later Lieutenant Governor (1999-2002). He was the Republican nominee for governor in 2002 but lost to Democrat Jennifer Granholm. He was married in 1972 and has 4 children.