Gustav Robert Kirchhoff (; 12 March 1824 – 17 October 1887) was a German physicist and mathematician who contributed to the fundamental understanding of electrical circuits, spectroscopy, and the emission of black-body radiation by heated objects.
He coined the term black-body radiation in 1860.
Several different sets of concepts are named "Kirchhoffs laws" after him, which include Kirchhoffs circuit laws, Kirchhoffs law of thermal radiation, and Kirchhoffs law of thermochemistry.
The Bunsen–Kirchhoff Award for spectroscopy is named after Kirchhoff and his colleague, Robert Bunsen.