Walter Rein (* December 10, 1893 in Stotternheim (now a district of Erfurt); † June 18, 1955 in Berlin) was a German composer and music educator.
Rein graduated from the teacher training seminar in Weimar and then worked as a teacher and choir director in Bürgel. He studied at the Berlin Academy for Church and School Music from 1924 and was also a composition student, including E. Lendvai and Richard Wetz. Later Rein taught at the State Music School in Weimar and at the Pedagogical Academies in Kassel (1930-32), Frankfurt am Main, and Weilburg. In April 1928, he participated in the founding meeting of the Nazi Teachers' League in Hof. After the Nazi "seizure of power" he was a member of the administrative advisory board of the Reichsmusikkammer. In 1935, he followed an appointment to the former Academy for Church and School Music in Berlin and became professor of musical folklore at the State College for Music Education. During the Nazi era, he composed various pieces in the spirit of those in power, including a solstice cantata in 1938. Rein joined the NSDAP in 1941 (membership number 8,740,882). In the final phase of World War II, he volunteered for the ''Volkssturm'' in December 1944.
From 1945, Rein worked as a freelance composer in Berlin. In 1948, he was denazified and rehabilitated in 1950. In 1954, he was reinstated, combined with immediate retirement.