German-born American organ builder.

Tannenberg came to the United States in 1740 with a group of colonists from the Moravian Church. He settled in Bethlehem, Pa., and worked there and in nearby Nazareth as a joiner. Soon after Johann Gottlob Klemm, an organ builder, joined the religious community in 1757, Tannenberg became his assistant and worked with him until Klemm's death in 1762.

In 1765 Tannenberg moved to Lititz, Pa., where he established a reputation as a meticulous and distinctive craftsman and carried on the South German tradition he had inherited from Klemm. All of the 32 organs he constructed are said to have been painted white with gold trim and to have had beautifully carved decorations. These instruments were mainly constructed for small churches requiring only one keyboard, or manual. Tannenberg's largest organs were built for Holy Trinity Lutheran Church, Lancaster, Pa. (1774), and Zion Lutheran Church, Philadelphia (1790); he also built other keyboard instruments such as harpsichords and virginals.

In his later years Tannenberg was assisted by Philip Bachmann (1762–1837), who succeeded him.