Rudolf Hoernes (7 October 1850 – 20 August 1912) was an Austrian geologist, born in Vienna.
He studied under Eduard Suess and became a Professor of geology in Graz.
He was known for his earthquake studies in 1878 and proposed a classification of earthquakes into subsidence earthquakes, volcanic earthquakes and tectonic earthquakes.
In 1893 he published a detailed textbook on earthquake theory (Erdbebenkunde) from a geological point of view.