20th-century classical composers

Thea Musgrave CBE (born 27 May 1928) is a Scottish composer of opera and classical music. She has lived in the United States since 1972.

Daniel Walter Chorzempa (December 7, 1944 – March 25, 2023) was an American organist, composer and architect.

Ulysses Simpson Kay (January 7, 1917 in Tucson, Arizona – May 20, 1995 in Englewood, New Jersey) was an American composer. His music is mostly neoclassical in style.

Mario Castelnuovo-Tedesco (3 April 1895 – 16 March 1968) was an Italian composer, pianist and writer. He was known as one of the foremost guitar composers in the twentieth century with almost one hundred compositions for that instrument. In 1939 he immigrated to the United States and became a film composer for Metro-Goldwyn-Mayer for some 200 Hollywood movies for the next fifteen years. He also wrote concertos for Jascha Heifetz and Gregor Piatigorsky.

Louis Charles Bonaventure Alfred Bruneau (3 March 1857 – 15 June 1934) was a French composer who played a key role in the introduction of realism in French opera.

Othmar Schoeck (1 September 1886 – 8 March 1957) was a Swiss Romantic classical composer, opera composer, musician, and conductor.
He was known mainly for his considerable output of art songs and song cycles, though he also wrote a number of operas, notably his one-act Penthesilea, which was premiered at the Semperoper in Dresden in 1927 and revived at the Lucerne Festival in 1999. He wrote a handful of instrumental compositions, including two string quartets and concertos for violin (for Stefi Geyer, dedicatee also of Béla Bartók's first concerto), cello and horn.

Marcel Michel, Baron Poot (7 May 1901 in Vilvoorde, Belgium – 12 June 1988 in Brussels) was a Belgian composer, professor, and musician.

Robert Walter Moevs (2 December 1920 – 10 December 2007) was an American composer of contemporary classical music. He was known for his highly chromatic music.

Hamish MacCunn, né James MacCunn (22 March 1868 – 2 August 1916) was a Scottish composer, conductor and teacher.
He was one of the first students of the newly founded Royal College of Music in London, and quickly made a mark. As a composer he achieved early success with his orchestral piece The Land of the Mountain and the Flood (1887), and, later, his first opera, Jeanie Deans (1894). His subsequent compositions did not match those two successes, and although he continued to compose throughout his life, he became best known as a conductor and teacher. He held teaching appointments at the Royal Academy of Music and the Guildhall School of Music.
As a conductor MacCunn served as musical director to the Carl Rosa, Moody-Manners and D'Oyly Carte opera companies, and worked with Thomas Beecham in the latter's London opera seasons in 1910 and 1915 and on tour.

Antonius Wilhelmus Adrianus de Leeuw (Rotterdam, 16 November 1926 - Paris, 31 May 1996) was a Dutch composer. He occasionally experimented with microtonality.