Justus Ferdinand Christian Loder (12 March 1753 – 16 April 1832) was a German anatomist and surgeon who was a native of Riga.

At Jena he was responsible for the establishment of an anatomical theatre and an Accouchierhaus (maternity house).

In 1780-81, at the expense of the Duke of Weimar, he took a scientific journey to France, England and Holland, a trip in which he made the acquaintance of several well-known physicians and scientists — Louis-Jean-Marie Daubenton, Jean-Louis Baudelocque, Félix Vicq-d'Azyr and John Hunter, among others.

After the closing of the University of Halle by Napoleon in 1806, he became personal physician to the Prussian royal family at Königsberg.

From 1794 to 1803 he published Tabulae anatomicae, which was a masterpiece containing a complete collection of anatomical illustrations of the human body.