Birgit Anette Rasmussen (née Olsen; born 2 April 1952 in Denmark) is a Danish linguist, professor at the University of Copenhagen and leader of the Roots of Europe research center. She is an expert on Proto-Indo-European and Indo-European languages in general, especially derivational morphology and the history of Armenian. She has also published important articles on linguistic reconstruction and the history of Latin, Greek, Anatolian and Germanic languages. She was married to Jens Elmegård Rasmussen, and her official surname is Rasmussen, but as a linguist she uses her maiden name Olsen to avoid confusion in references.