Otto Marburg (May 25, 1874 – June 13, 1948) was an Austrian neurologist known for his contributions to the understanding of multiple sclerosis and for advances in neurooncology.

Marburg was born in Römerstadt in Moravia, Austria-Hungary (today Rýmařov, Czech Republic).

Following the 1938 Anschluss, Marburg was forced to emigrate to the United States as a refugee.

Arriving in New York City, he joined Columbia University's College of Physicians and Surgeons as a clinical professor of neurology.

He was the author of several standard texts about the nervous system, and a subtype of multiple sclerosis (Marburg multiple sclerosis) has been named after him.