Zoltan J. Acs (born 1947) is an American economist. He is a professor at George Mason University, where he teaches in the School of Public Policy and directs the Center for Entrepreneurship and Public Policy. He is a Research Scholar at the Max Planck Institute for Economics in Jena, Germany, and Scholar-in-Residence at the Kauffman Foundation. A leading advocate of the importance of entrepreneurship for economic development, he is co-editor and founder of Small Business Economics, an entrepreneurship and small business publication. He has published more than 100 articles and 20 books, including articles in the American Economic Review, Review of Economics and Statistics, Kyklos, Journal of Urban Economics, Economica, Research Policy and Science Policy. Acs has served as Chief Economist at the U.S. Small Business Administration.
In 2001, Acs was awarded the Global Award for Entrepreneurship Research, "for his research on the role of small firms in the economy, especially the role of small firms in innovation" along with David B. Audretsch. He has also been awarded an honorary degree from the University of Pecs.
- Why Philanthropy Matters: How the Wealthy Give and What it Means to Our Economic Well-being, Princeton University Press, 2013. 
- The Global Entrepreneurship and Development Index 2013, with Laszlo Szerb and Erkko Autio, Edward Elgar Publishers, 2013. 
- The Global Entrepreneurship and Development Index 2012,with Laszlo Szerb, Edward Elgar Publishers, 2012.
- Handbook of Entrepreneurship Research,2nd edition, with David B. Audretsch, eds., Springer Publishers, 2010. 
- The Knowledge Spillover Theory of Entrepreneurship,ed., Cheltenham: Edward Elgar, 2010. 
- Entrepreneurship, Growth and Public Policy, with David B. Audretsch and Robert Strom, eds., Cambridge University Press, 2009. 
- Entrepreneurship, Growth and Public Policy, Edward Elgar, Cheltenham, 2008.
- Public Policy in an Entrepreneurial Economy: Creating the Conditions for Business Growth, with Roger Stough eds., Boston: Springer 2008. 
- Obesity, Business and Public Policy, Edward Elgar Publishing Ltd, 2007. 
- Innovation and Small Firms, with David B. Audretsch, MIT Press, 1990.
- "R&D Spillovers and Recipient Firm Size," with David B. Audretsch and Maryann P. Feldman, Review of Economics and Statistics, Vol. 76, No. 2, May 1994, 336-340.
- "Small-Firm Entry in U.S. Manufacturing," with David B. Audretsch, Economica, Vol. 56, No. 2, May 1989, 255-266.
- "Innovation, Market Share, and Firm Size," with David B. Audretsch, Review of Economics and Statistics, Vol. 69, No. 4, November 1987, 567-575.
-  George Mason U. Web site
- "2001 Award Winners". Global Award for Entrepreneurship Research. Retrieved 24 July 2014.
- [ http://books.google.com/books?id=JvdsPgAACAAJ&dq=The+Knowledge+Spillover+Theory+of+Entrepreneurship&hl=en&sa=X&ei=JQ75U-KhEIaPyASFioGADw&ved=0CCUQ6AEwAA]