The level of entrepreneurship differs considerably across countries and periods. Both the causes and consequences of entrepreneurship are a matter of extensive scientific debate as well as of great policy importance. A high level of entrepreneurial activity is assumed and shown to contribute to innovative activities, competition, economic growth and job creation. The present paper deals with the determinants of entrepreneurship. An eclectic theory of entrepreneurship is introduced. This eclectic theory provides an integrated framework, drawing on disparate strands of literature, to create a better understanding of the different role that entrepreneurship plays in different countries and time periods. This framework is designed to guide future empirical research in this area and to provide insights for policymakers striving to promote entrepreneurship.