Oliger Jacobaeus (1650-1701), also known as Holger Jacobi, was a Danish physician and naturalist.
He was professor of medicine, philosophy, history, and geography at University of Copenhagen.He authored several treatises, notably, Compendium Institutionum Medicarum, De Ranis dissertatio, Romae, Bartholomei Scalae equitis Florentini historia Florentinorum and others.
He was appointed by Frederick IV of Denmark as counsellor in his court of justice in 1698 as a token of appreciation.