Kurt Julian Weill (March 2, 1900 – April 3, 1950) was a German-Jewish composer, active from the 1920s, and in his later years in the United States. He was a leading composer for the stage who was best known for his fruitful collaborations with Bertolt Brecht. With Brecht, he developed productions such as his most well known work The Threepenny Opera, a Marxist critique of capitalism, which included the ballad "Mack the Knife". Weill was a socialist who held the ideal of writing music that served a socially useful purpose. He also wrote a number of works for the concert hall, as well as several Judaism themed pieces.

Kurt Julian Weill was born on March 2, 1900, the third of four children to Albert Weill (1867–1950) and Emma Weill nйe Ackermann (1872–1955). He grew up in a religious Jewish family in the "Sandvorstadt", the Jewish quarter in Dessau, Germany, where his father was a cantor. At the age of twelve, Kurt Weill started taking piano lessons and made his first attempts at writing music; his earliest preserved composition was written in 1913 and is titled Mi Addir. Jewish Wedding Song.

In 1915, Weill started taking private lessons with Albert Bing, Kapellmeister at the "Herzogliches Hoftheater zu Dessau", who taught him piano, composition, music theory, and conducting. Weill performed publicly on piano for the first time in 1915, both as an accompanist and soloist. The following years he composed numerous Lieder to the lyrics of poets such as Eichendorff, Arno Holz, and Anna Ritter, as well as a cycle of five songs titled Ofrahs Lieder to a German translation of a text by Yehuda Halevi.

Weill graduated with an Abitur from the Oberrealschule of Dessau in 1918, and enrolled at the Berliner Hochschule fьr Musik at the age of 18, where he studied composition with Engelbert Humperdinck, conducting with Rudolf Krasselt, and counterpoint with Friedrich E. Koch, and also attended philosophy lectures by Max Dessoir and Ernst Cassirer. The same year, he wrote his first string quartet (in B minor).