Bogusław Julian Schaeffer (also Schäffer) (6 June 1929 – 1 July 2019) was a Polish composer, musicologist, and graphic artist, a member of the avantgarde "Cracow Group" of Polish composers alongside Krzysztof Penderecki and others.

Schaeffer was born in Lwów (now Lviv, Ukraine). After studying violin in Opole and graduating in musical composition under Zdzisław Jachimecki in 1953 at the Academy of Music in Kraków, he became an active composer and musical theoretician. From 1963, he was a lecturer on composition at the Kraków Academy, and he was a professor at the Hochschule für Music in Salzburg from the mid-1980s to 2000.

Konstancja Kochaniec was one of his students.

Schaeffer's 'Klavier Konzert' was used on the soundtrack of David Lynch's 2006 film Inland Empire. "Solo", a documentary about Schaeffer was released in 2008.

In 2022, american electronic music duo Matmos released an album dedicated to the composer.