Per Gunnar Fredrik de Frumerie (20 July 1908, Nacka, Stockholm County — 9 September 1987, Täby, Stockholm County) was a Swedish composer and pianist. He was the son of architect Gustaf de Frumerie and Maria Helleday.
After studying piano in Stockholm and Vienna, he studied under Alfred Cortot in Paris. He then studied at the Royal College of Music, Stockholm 1923–1928. He taught the piano at the same college from 1945 to 1974.
His compositions covered a wide area, from grand opera to piano miniatures, but he is best remembered for his piano works. His works possess a Brahmsian complexity mixed with an impressionistic elegance. One can relate his music to composers like Lars-Erik Larsson or Wilhelm Peterson-Berger.
Although not noted for his theatre work, he did write an opera, Singoalla (1940). He wrote many songs, often to words by Pär Lagerkvist. The cello concerto (1984) has an interesting history. It was adapted from his second cello sonata. He then adapted it into a trombone concerto, and was his last completed work. It was specifically written for the Swedish trombone virtuoso Christian Lindberg.