Johann Georg Tralles (15 October 1763 – 19 November 1822) was a German mathematician and physicist. He was born in Hamburg, Germany and was educated at the University of Göttingen beginning in 1783. He became a professor at the University of Bern in 1785. In 1810, he became a professor of mathematics at the University of Berlin. In 1819, he discovered the Great Comet of 1819, Comet Tralles, named after him. He was the inventor of the alcoholometer, a device for measuring the amount of alcohol in a liquid.