The National Theater Orchestra, Mannheim, in German and in full the Musikalische Akademie des Nationaltheater-Orchesters Mannheim, is one of Europe's oldest orchestral ensembles. The orchestra has numbered some of Germany's greatest conductors among its music directors, but it has rarely been heard on recordings.

The National Theater Orchestra, Mannheim, was founded in 1778. The group was founded as an "Académie des amateurs," following French models, and the "musical academy" of the German name comprises not only the players but also their supporters. That points to a unique feature of the orchestra's organization: it has a democratic structure, with associated programmatic and financial independence, safeguarded by a board of directors and board of trustees. The orchestra has an unbroken history of general music directors (they held the title Kapellmeister or Hofkapellmeister until 1923) dating back to 1779 when conductor Ignaz Fränzl took up the baton; he remained in the position until 1803. Many of the group's music directors have also been composers. Among their ranks are a number of legendary figures of German music, including Felix Weingartner (1889 - 1891), Wilhelm Furtwängler (1915 - 1920), and Erich Kleiber (1922 - 1923). Notable music directors in the 21st century have included Adam Fischer (2000 - 2005), Dan Ettinger (2009 - 2016), and Alexander Soddy (since 2016). The orchestra performs at Mannheim's Operngraben and (eight times a year) the Mozart Hall of the Rosengarten.

Despite its renown, the National Theater Orchestra, Mannheim has recorded only occasionally. On the Ars Sonandi label, it released a recording of Friedmann Dressler's Der symphonische Ring arrangements of Wagner's Ring Cycle operas. The orchestra has established its own Musikalische Akademie Mannheim label, on which it released a recording of Bruckner's Symphony No. 9 in D minor. In 2020, the orchestra released a recording of Messiaen's Turangalîla-Symphonie on the Oehms Classics label. ~ James Manheim, Rovi