Karl Pilß (4 April 1902 – 22 June 1979) was an Austrian pianist, conductor, and composer. He also was a painter.
Born in Vienna, he studied piano and music theory with Ferdinand Rebay from 1918 to 1922; from 1924 to 1927 composition with Franz Schmidt at the Vienna Academy of Music; from 1925 to 1927 conducting and to become a Kapellmeister with Robert Heger.
From 1928 to 1934 he worked as répétiteur at the Wiener Singakademie.
In 1932, Clemens Krauss hired him as assistant choir director for Ferdinand Grossmann at the Vienna State Opera.
He also taught piano and music theory at the Wiener Volkskonservatorium that Grossman had established. From 1960 to 1968 he taught at the Vienna Academy of Music.
He held various positions such as chorus master of the railroad employees choir, worked privately as a répétiteur from 1941 to 1966. He directed various choirs, including the Wiener Singverein.
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.