Lothar Bisky (born 17 August 1941) is the chairman of the Party of Democratic Socialism, a socialist political party with its base in the east of Germany.

He lived in the former East Germany and joined the Socialist Unity Party in 1963. In 1990 he was a member of the Volkskammer and since 1990 he has been a member of the state parliament in Brandenburg.

He was chairman of the PDS from 1993 until his resignation in 2000 over a defeat for the executive committee on support for United Nations military intervention. He was re-elected chairman in 2003. Bisky is seen to be on the social democratic wing of the party.

He was rector of the University of Film and Television (Potsdam-Babelsberg) from 1986 to 1990. Since 1991 he has been on the board of directors of regional television channel ORB.