Otto Erich Deutsch (September 5, 1883 - November 23, 1967) was an Austrian musicologist. He is best known for his catalogue of the works of Franz Schubert (1951) - it is from this that the D numbers used to identify Schubert's pieces are drawn.

He also wrote many articles on Schubert and Wolfgang Amadeus Mozart, and compiled "documentary biographies" (collections of contemporary documents concerning the subject) on Schubert, Mozart and George Frideric Handel.