Anders Jonas Ångström (; 13 August 181421 June 1874) was a Swedish physicist and one of the founders of the science of spectroscopy.
Ångström is also well known for his studies of astrophysics, heat transfer, terrestrial magnetism, and the aurora borealis. In 1852, Ångström formulated in Optiska undersökningar (Optical investigations), a law of absorption, later modified somewhat and known as Kirchhoff's law of thermal radiation.