Collegium Vocale Köln is a German vocal ensemble, founded in 1966 as a quintet when its members were still students at the Rheinische Musikschule in Cologne. It is directed by Wolfgang Fromme, who also sings tenor in the ensemble. They are best known as the group for which Karlheinz Stockhausen composed Stimmung in 1968, a work which they had performed more than three hundred of times throughout the world by 1986. The original impetus for the ensemble's founding, however, was an appearance by Alfred Deller at the Cologne Courses for Early Music, and the group has always performed both early and contemporary works.

In addition to Stimmung, the Collegium Vocale performed other works by Stockhausen, notably as part of the ensemble of musicians who appeared with him at Expo '70 in Osaka, Japan, between March and September 1970, where individual singers of the group performed Spiral for a soloist with a short-wave radio. On 5 June 1971 the Collegium Vocale participated in the world premiere of Stockhausen's Sternklang in the Tiergarten in Berlin, and appeared also in subsequent performances in the Englischer Garten in Munich, at the Shiraz Arts Festival in 1972, in the Parc Franck Delmas at the La Rochelle Festival in 1974, and in the Parc de Saint-Cloud in 1975. Four members of the group also took part in a studio recording of the work made in June 1975. In the meantime, they had also participated in the world premiere of his Alphabet für Liège on 23 September 1972.