Jens Böhrnsen (born 12 June 1949) is a German politician of the SPD.
From 2005 to 2015, he has served as the President of the Senate and Mayor of the Free Hanseatic City of Bremen, that is, the head of government of the city-state Free Hanseatic City of Bremen.
From 1 November 2009 until 31 October 2010 he was President of the Bundesrat and ex officio deputy to the President of Germany.
Because of that he was acting head of state of Germany after the resignation of President Horst Köhler on 31 May 2010 and before the election of Christian Wulff as Köhler's successor on 30 June 2010.
After voting for the SPD losses of more than five percentage points in the state election on May 10, 2015 Böhrnsen declared the next day that he would retire as head of government.
His successor in the office of the Bremen government was Carsten Sieling, who was officially nominated on 18 May 2015 by the Bremen SPD.
He is a lawyer by profession and served as a judge in Bremen from 1978 to 1995, when he became a full-time politician.