Karl-Birger Blomdahl (October 19, 1916 – June 14, 1968) was a Swedish composer and conductor born in Växjö. He was educated in biochemistry, but was primarily active in music and by his experimental compositions he became one of the big names in Swedish modernism. His teachers included Hilding Rosenberg (). He died in Kungsängen, Stockholm.
His third symphony, Facettes - a work in one subdivided movement (described here as a twelve-tone variation-form piece) - from 1950 is a major contribution to the repertoire.