Johann Caspar Kerll (9 April 1627 – 13 February 1693) was a German baroque composer and organist. He is also known as Kerl, Gherl, Giovanni Gasparo Cherll and Gaspard Kerle.
Born in Adorf the son of an organist, Kerll showed outstanding musical abilities at an early age, and was taught by Giovanni Valentini, court Kapellmeister at Vienna. Kerll became one of the most acclaimed composers of his time, known both as a gifted composer and an outstanding teacher. He worked at Vienna, Munich and Brussels, and also travelled widely. His pupils included Agostino Steffani, Franz Xaver Murschhauser, and possibly Johann Pachelbel, and his influence is seen in works by Handel and Johann Sebastian Bach: Handel frequently borrowed themes and fragments of music from Kerll's works, and Bach arranged the Sanctus movement from Kerll's Missa superba as BWV 241, Sanctus in D major.
Although Kerll was a well-known and influential composer, many of his works are currently lost. The losses are particularly striking in vocal music, with all 11 known operas and 24 offertories missing. The surviving oeuvre shows Kerll's mastery of the Italian concerted style, employed in almost all of his masses, and his highly developed contrapuntal technique. He was influenced by Heinrich Schütz in his sacred vocal music, and by Girolamo Frescobaldi in keyboard works.
Kerll was the son of Caspar Kerll and Catharina Hendel (married 1626). He was born in 1627 in Adorf, where his father served as organist of the Michaeliskirche (appointed after building the church organ with Jacob Schädlich). Caspar Kerll probably gave music lessons to his son, who apparently demonstrated exceptional musical abilities; by 1641 he was already composing and sometime later during the early 1640s he was sent to Vienna to study under Giovanni Valentini, court Kapellmeister and composer. Kerll's professional career started in Vienna, where he served as organist, and continued in approximately 1647/8, when Archduke Leopold Wilhelm of Austria (then the governor of the Spanish Netherlands) employed him as chamber organist for the new residential palace in Brussels.