John J. Diehl, Jr. (born August 28, 1965) is an American attorney and a Republican former member of the Missouri House of Representatives. He represented the 89th district, which includes Ballwin, Chesterfield, Country Life Acres, Crystal Lake Park, Des Peres, Frontenac, Huntleigh, Kirkwood, Ladue, Manchester, and Town and Country, from 2009 to 2015. Prior to redistricting he represented the 87th district from 2009-2012. Diehl was elected Speaker of the Missouri House of Representatives in 2013 and took office in January 2015. Diehl resigned on May 14, 2015 after a scandal came to light regarding inappropriate messages exchanged with an intern.