Georg Daniel Speer (2 July 1636, Wroclaw, Poland – 5 October 1707, Göppingen, Germany) was a German composer and writer of the Baroque. He published a treatise on music, but also works of fiction. As a composer, Speer for example produced music for trombones. Keyboard miniatures have also survived. He is known for his Sonata No. 29 from Die Bänkelsängerlieder for brass quintet, which is often played at weddings and formal occasions.