Robert von Ostertag (March 24, 1864 – October 7, 1940) was a German veterinarian who was a native of Schwäbisch Gmünd.
Ostertag's meat inspection act of 1900 greatly reduced incidences of bovine tuberculosis in human beings.
He was the author of numerous publications in veterinary science, and is remembered for his influential Lehrbuch für Fleischbeschauer ("Handbook of Meat Inspection"), a book that was later translated into English.
His name is lent to Ostertagia, a genus of attenuated nematodes of the family Trichostrongylidae.
These organisms are found in cysts on the wall of the abomasum of cattle and other ruminants.