5. United States:  Although some of the most prestigious and expensive school of learning's in the world are located in the United States, still the professors working in the public universities here bag less as compared to countries like Canada, Italy, South Africa and India highlighted above. Professors working in the public universities in the U.S. earn an average of $ 6,054 per month. The top public universities of U.S. are Georgia Institute of Technology, University of California at Berkeley and Los Angeles and University of Illinois.