The Niels Bohr Institute is part of the Niels Bohr Institute for Astronomy, Physics and Geophysics of the University of Copenhagen.

The Institute was founded in 1921. The famous Danish theoretical physicist Niels Bohr was on its faculty from 1914 onwards. On Niels Bohr's 80th birthday - October 7, 1965 - the Institute for Theoretical Physics of the University of Copenhagen officially became The Niels Bohr Institute.

During the 1910s, 1920s, and 1930s, the Institute was the center of the developing disciplines of atomic physics and quantum physics. Physicists from across Europe (and sometimes further abroad) often visited the Institute to confer with Bohr on new theories and discoveries. The Copenhagen interpretation of quantum mechanics is named after work done at the Institute during this time.