Robert J. Osterhaus (born January 30, 1931) is an American politician in the state of Iowa.
Osterhaus was born in Dyersville, Iowa. He attended the University of Iowa and is a pharmacist. A Democrat, he served in the Iowa House of Representatives from 1995 to 2005 (34th district from 1995 to 2003 and 25th district from 2003 to 2005).