Dietmar Gerhard Bartsch (born 31 March 1958) is a German politician who has served as co-chair of The Left parliamentary group in the Bundestag since 2015.

From 1986 until 1990, he studied at the Academy for Social Sciences at the Communist Party of the Soviet Union headquarters in Moscow, before returning to the Junge Welt as their business executive.

[1] In the 2002 German federal election, Bartsch was one of four lead candidates for the PDS, alongside Gabi Zimmer, Petra Pau, and Roland Claus.

In January 2012, Der Spiegel reported that 27 of the Left's 76 members of the Bundestag were under surveillance by the Federal Office for the Protection of the Constitution, including Bartsch.

The surveillance of Bundestag deputies, including many such as Bartsch who were not connected with groups classified as anti-constitutional, was criticised by the FDP, SPD, and Greens.

[6] Bartsch was elected co-leader of the Left's Bundestag group in 2015 alongside Sahra Wagenknecht, succeeding long-time leader Gregor Gysi.

Ahead of the 2021 federal election, Bartsch was once again chosen as one of The Left's two lead candidates alongside new party co-leader Janine Wissler.

[10] After the formation of BSW—For Reason and Justice, it was predicted that the remaining MPs for The Left could split along Bartsch's supporters and the party leadership.

He also argued against characterising East Germany as an injustice state (Unrechtsstaat), describing the usage of the term as a "cudgel" lacking nuance.

[19] Bartsch denied this, as well as allegations that he sought to succeed Lafontaine as chairman, and defended his record as federal managing officer.

Most controversially, each was classified according to allegiance: allies were labeled Z for "reliable", others U for "independent", and rivals L for "left" or "Lafodödel", a derisive term for supporters of Lafontaine.

Bartsch stated that the document represented the "relatively normal process" of categorising regional association and factions, not party opponents, and that he only used the term "Lafodödel" in a single email.

Upon the publication of the Die Welt article, prominent members Jan van Aken, Martina Renner, and Klaus Ernst expressed outrage at the existence of Bartsch's document.