Carl Oscar Boije af Gennäs

Carl Oscar (Oskar) Boije af Gennäs (7 July 1849 – 1923), was a Swedish collector of guitar sheet music.

Boije af Gennäs was born in Hasslövs socken, Halland County, Sweden. He was descended from the Swedish-Finnish noble family Boije af Gennäs and worked as a mathematician at the life insurance company Victoria in Stockholm.

Boije af Gennäs was an amateur guitarist and composer. He composed Marcia Funebre in memory of Otto Hammerer. The piece was published in Freie Vereinigung zur Förderung guter Guitarmusik, eingetragener Verein, Sitz i Augsburg, (Free Society for the promotion of good Guitar-music, seat at Augsburg), April 1905, volume 8.

Boije af Gennäs was a guitar music collector, mainly of music from the 19th century. His collection included nearly 1,000 works, including sheet music by Dionisio Aguado, Matteo Carcassi, Ferdinando Carulli, Mauro Giuliani, Luigi Rinaldo Legnani and Fernando Sor.

The collection also contained original manuscripts by J. K. Mertz. The collection, which only contained music for guitar, was donated to The Music and Theatre Library of Sweden (formerly The Music Library of Sweden and earlier The Library of The Swedish Academy of Music) in Stockholm. The collection is digitized and is available online via Boijes collection at the Music and Theatre Library of Sweden.