Børge Bak (31 December 1912 – 22 February 1990), Knight of the Order of the Dannebrog 1st Class, was a Danish polymath, inventor, chemist and professor of molecular spectroscopy at the University of Copenhagen, best known for his early contributions to the field of Molecular Spectroscopy.
Bak travelled widely as a visiting Professor, including to the University of California, Berkeley (1969) and the University of Bologna (1976).
He served as a nominator to the Nobel Committee for Chemistry, was the recipient of the 1957 Esso Foundation's prize for outstanding technical science research, and was elected a member of the Royal Danish Academy of Sciences in 1958.