Rudolf Stähelin, surname also spelled Staehelin was a Swiss internist.
He studied medicine at the Universities of Basel, Tübingen and Munich, obtaining his doctorate at Basel in 1901.
He briefly served as an assistant physician at the Civic Hospital in Basel, then was a lecturer at the Universities of Basel (from 1902), Göttingen (1906) and Berlin (from 1907). From 1911 until 1943, he was a professor of internal medicine and director of the medical clinic at Basel. His research involved studies on tuberculosis, respiratory, circulatory, metabolic and infectious diseases.
With Gustav von Bergmann, he published the second edition of the Handbuch der inneren Medizin (1925-1931).