Kirchhoff was a German physicist 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 1862. Several different sets of concepts were named "Kirchhoff's laws" by Kirchhoff, concerning such diverse subjects as black-body radiation and spectroscopy, electrical circuits, and thermochemistry. "Kirchhoff's laws" relating to electrical circuits built on the theoretical work of fellow German physicist Georg Simon Ohm. Kirchhoff used spectroscopy to determine the chemical composition of the sun. The Bunsen–Kirchhoff Award for spectroscopy is named after him and his colleague, Robert Bunsen.