Karl Pilß (4 April 1902 – 22 June 1979), alternative spelling Pilss, was an Austrian pianist, conductor, and composer.
In 1932, Clemens Krauss hired him as assistant choir director for Ferdinand Grossmann at the Vienna State Opera.
He held various positions such as chorus master of the railroad employees choir, worked privately as a répétiteur from 1941 to 1966.
He was also director of studies at the Salzburg Festival from 1934 to 1966, where he had the opportunity to co-operate in productions with conductors such as Arturo Toscanini, Bruno Walter, Hans Knappertsbusch, Wilhelm Furtwängler, Karl Böhm, and Herbert von Karajan.
As a composer he was influenced by the music of Gustav Mahler, Richard Strauss and his teacher Franz Schmidt.