The Monday Group (sv. Måndagsgruppen) was an influential group of Swedish composers, musicians and musicologist. The group was formed in 1944 and gathered the most prominent composers of the time in the apartment of the group's leader Karl-Birger Blomdahl. During the meetings the members discussed music aesthetics and compositional process and technique. Among the members were Claude Loyola Allgén, Sven-Erik Bäck, Sven-Eric Johanson, Hans Leygraf, Claude Génetay, Eric Ericson and Ingmar Bengtsson.
Musically the group had a modernist approach inspired by German avant-garde. Most of the members rejected the late-romantic and neo-classical ideals that were present in Sweden at the time.
Måndagsgruppen participated in cultural and musical debate and played an important role in the stylistic changes towards modernism that came during 1950–1960. Several of the members becamer professors in composition.