Lothar Zagrosek (born 13 November 1942 in Otting, Germany) is a German conductor. As a youth, he sang in the Regensburg Cathedral choir, including performances as the First Boy in The Magic Flute at the 1954 Salzburg Festival. From 1962 to 1967, Zagrosek studied conducting with Hans Swarowsky, István Kertész, Bruno Maderna and Herbert von Karajan.
Zagrosek was chief conductor of the Vienna Radio Symphony Orchestra from 1982 to 1986. He was principal guest conductor of the BBC Symphony Orchestra from 1985 to 1988. Between 1990 and 1992, he conducted regularly at the Leipzig Opera. In 1995, he became principal guest conductor of the Junge Deutsche Philharmonie. From 1997 to 2006, he was chief conductor at the Württemberg opera house in Stuttgart. From 2006 to 2011, he was chief conductor of the Konzerthausorchester Berlin, the former Berlin Symphony Orchestra (Berliner Sinfonie-Orchester).
Among Zagrosek's commercial recordings are several issues in Decca's Entartete Musik series, including the following works:
Zagrosek conducted and recorded Wagner's opera cycle Der Ring des Nibelungen with the Stuttgart State Opera on the Naxos label (NXS 8660170). In addition, Zagrosek has recorded contemporary music, including works of Michael Torke.