Wouter Jacob Bos (born July 14, 1963) was a Dutch minister of finance, deputy Prime Minister and leader of the Dutch Labour Party. He won the election of Dutch Labour Party leader, defeating Jouke de Vries. He led the party until March 12, 2010, the day he left. His successor is Job Cohen, who used to be the mayor of Amsterdam. He left because he wanted to spend more time with his family.