Johann Heinrich Hartmann Bätz (1 January 1709 – 13 December 1770) was a German-Dutch organ builder.
Bätz was born in Frankenroda (Thuringia). He learned the organ-building profession in Gotha under the auspices of Christoph Thielemann. He came to Holland in 1733 where he probably first worked for Christiaan Müller, builder of the organ in the Sint-Bavokerk in Haarlem. In 1739 he set up his own firm in Utrecht. His instruments were considered stupendous, commanding the admiration of every one who hears, and even sees them. The organ of Zierikzee, which was built in 1770, had 56 voices and 3108 pipes. Bätz was paid 19,500 florins for this organ, which burned down in 1832. He erected other organs of similar magnitude in the large churches of Gorinchem, Utrecht, Woerden, Benschop, etc. He died in Utrecht. His sons Gideon (born 1851) and Christoffel (born 1855), who lived their entire life in Utrecht, succeeded their father in the business.