Johann (Georg) Andreas Stein (16 May 1728 in Heidelsheim – 29 February 1792 in Augsburg), was a maker of keyboard instruments from Germany. He built organs, clavichords, harpsichords and pianos.^[1]

In the beginning Stein learned the craft from his father in Heidelsheim. In 1748 to 1749 he was visiting two different workshops: one of Johann Andreas Silbermann in Strasbourg and the other of Frantz Jacob Spath in Regensburg.^[1] Later Stein played an important role in the history of piano and was responsible for the design of the Viennese hammer action. In 1777 Stein met Wolfgang Amadeus Mozart for the first time.^[2] The composer used Stein's pianos in his public performances in Augsburg later that year.^[3] He was fond of Stein's pianos and shared his admiration in a letter to his father.^[2]

Only a few instrument by Stein survived until the XXI century. One clavichord that was bought by Leopold Mozart is now displayed in the Budapest National Museum.

• The Piano: Viennese Instruments
• Hungarian National Museum. Mozart’s clavichord made by Stein.^{[permanent dead link]}
• Mozart's pianos. BBC.
• A modern replica of a Stein piano Archived 2021-12-05 at the Wayback Machine