20th-century Belgian male musicians

Jean-Baptiste Frédéric Isidor, Baron Thielemans (29 April 1922 – 22 August 2016), known professionally as Toots Thielemans ([tuts tiləmans]), was a Belgian jazz musician. He was mostly known for playing the chromatic harmonica, as well as his guitar and whistling skills, and composing. According to jazz historian Ted Gioia, his most important contribution was in "championing the humble harmonica", which Thielemans made into a "legitimate voice in jazz". He eventually became the "preeminent" jazz harmonica player.His first professional performances were with Benny Goodman's band when they toured Europe in 1949 and 1950. He emigrated to the U.S. in 1951, becoming a citizen in 1957. From 1953 to 1959 he played with George Shearing, and then led his own groups on tours in the U.S. and Europe. In 1961 he recorded and performed live one of his own compositions, "Bluesette", which featured him playing guitar and whistling. In the 1970s and 1980s, he continued touring and recording, appearing with musicians such as Oscar Peterson, Ella Fitzgerald, Sarah Vaughan, Bill Evans, Dizzy Gillespie, Kenny Werner, Pat Metheny, Jaco Pastorius, Mina Mazzini, Elis Regina, Quincy Jones, George Shearing, Natalie Cole, Billy Joel, Paul Simon, and Paquito D'Rivera.
Thielemans recorded the soundtracks for The Pawnbroker (1964), Midnight Cowboy (1969), The Getaway (1972), Cinderella Liberty (1973), The Sugarland Express (1974) and Looking for Mr. Goodbar (1977). His harmonica theme song for the popular Sesame Street TV show was heard for 40 years. He often performed and recorded with Quincy Jones, who once called him "one of the greatest musicians of our time." In 2009 he was designated a Jazz Master by the National Endowment for the Arts, the highest honor for a jazz musician in the United States.

Jean-Jacques Blairon (9 August 1947 – 14 July 2020) was a Belgian musician active in the 1980s under the name J. J. Lionel.

Flor Alpaerts (Antwerp, 12 September 1876 – Antwerp, 5 October 1954) was a Belgian conductor, pedagogue and composer. He graduated from the Vlaamse Muziekschool in 1901.
He was artistic director of the Peter Benoit Foundation, co-director of the Royal Flemish Opera and a member of the Royal Academy of Belgium. As a composer he became the leading Flemish impressionist, with the symphonic poem Pallieter (1921-1924).
Alpaerts left behind an extensive body of work. He first composed in an impressionist style, later expressionist, and finally neo-classical. He drew his inspiration from Flemish life. Peter Benoit was his great model, but he adapted Benoit's principles and gave Flemish music a modern mode of expression and a contemporary face.
He wrote above all for the symphony orchestra, but he also wrote incidental music, an opera, many Flemish songs, chamber music and work for brass bands and wind ensembles.
Notable students include the two composers, Denise Tolkowsky and Ernest Schuyten.

Marie Alphonse Nicolas Joseph Jongen (14 December 1873 – 12 July 1953) was a Belgian organist, composer, and music educator.

Éric Legnini (born 20 February 1970 in Huy, near Liège, Belgium) is a Belgian jazz pianist and bandleader of the Éric Legnini Trio.Legnini was born into an artistic family from Italy. The family immigrated to Belgium, where he started playing the piano at age 6 and initiated in jazz in his teens. In 1988 he traveled to the United States for two years to study American jazz. He returned as a teacher of jazz piano at the Brussels Royal Conservatory of Music, where he met Jacques Pelzer. The result was the Pelzer album Never Let Me Go with guest stars Barney Wilen and Michel Graillier.
He started to play piano in the Stefano di Battista Quartet. In the 1990s, he worked with Flavio Boltro (trumpet) and Stefano Di Battista (saxophone) forming the jazz ensemble Éric Legnini Trio that caught attention in the 1990s.
He has played with fellow artists like Aldo Romano, Belmondo Quintet, John Ruocco, Félix Simtaine, Jeanfrançois Prins, Michel Hatzigeorgiou, Dré Pallemaerts, Emanuele Cisi, Toninho Horta, Philip Catherine, Serge Reggiani, Hein van de Geyn, Marcia Maria, Jacques Pelzer, André Ceccarelli, Éric Le Lann, Paco Sery and others.
Legnini had great admiration for the works of Phineas Newborn, dedicating the piece The Memphis Dude to him. The track appears in his album Miss Soul.
Legnini won "Octave de la musique jazz" in 2006 and "Instrumental album of the year" during 2011 Victoires du jazz for his album The Vox.

Pierre Chrétien Degeyter (French: [pjɛʁ kʁetjɛ̃ də ɡetɛʁ], Flemish: [də ˈɣɛitər]; 8 October 1848 – 26 September 1932) was a Belgian-French socialist and a composer, known for writing the music of The Internationale.

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

Jean Absil (23 October 1893 – 2 February 1974) was a Belgian composer, organist, and professor at the Brussels Conservatoire.