Francis G. Slay (born March 18, 1955) is an American politician and lawyer. He was the 45th Mayor of St. Louis, Missouri from 2001 to 2017. Slay is the longest-serving mayor in St. Louis history. His fourth term started in April 2013. He announced on April 8, 2016 that he would not seek another term as mayor. He is registered in the Democratic Party.