Bernhard Siegfried Albinus (originally Weiss) (February 24, 1697 - September 9, 1770) was a German anatomist.

Albinus was born at Frankfurt an der Oder, where his father, Bernhard Albinus (1653-1721), was professor of the practice of medicine. In 1702 the latter was transferred to the chair of medicine at Leiden University, and it was there that Bernhard Siegfried began his studies, having for his teachers such men as Boerhaave and Nikolaus Bidloo. Having finished his studies at Leiden, he went to Paris, where, under the instruction of Sebastien Vaillant (1669-1722), Jacob Winslow (1669-1760) and others, he devoted himself especially to anatomy and botany. After a year's absence he was, on the recommendation of Boerhaave, recalled in 1719 to Leiden to be a lecturer on anatomy and surgery. Two years later he succeeded his father in the professorship of these subjects, and speedily became one of the most famous teachers of anatomy in Europe, his classroom being resorted to not only by students but by many practising physicians. In 1745 Albinus was appointed professor of the practice of medicine, being succeeded in the anatomical chair by his brother Frederick Bernhard (1715-1778), who, as well as another brother, Christian Bernhard (1700-1752), attained considerable distinction. Bernhard Siegfried, who was twice rector of his university, died at Leiden.