Swedish pianist, conductor, arranger and composer. Born as Stig Alvar Jonsson in Norrköping, Sweden, August 8, 1916 and died in Geiranger, Norway, August 9, 1985.

He studied at the Royal Academy of Music in Stockholm 1934–1943, and from 1944–1950 was attached to Kungliga Operan. From 1951 he was an arranger and conductor at Sveriges Radio, where he succeeded Sune Waldimir, and in 1956 became head of the music section at Sveriges Radio. His repertoire includes ballet music, orchestral and chamber works as well as songs.

During his studies, he was pianist and arranger for Kvartetten Synkopen.

Rybrant became a member of the Swedish Royal Academy of Music in 1974.

Son to Ernst Jonsson and nephew to Gösta Rybrant.