This paper examines the separate productive impacts of direct and indirect exporting to further our understanding of the mechanisms underlying learning‐by‐exporting effects by utilizing a method that allows us to check the robustness of the results to the selection on unobservables. We found that the productivity effects of exporting are mainly associated with direct exporting, indicating that knowledge spillover, and thus, productive impact of exporting grows with increased interaction with international firms and consumers. Indirect exporters are unlikely to be able to efficiently exploit the productive capacity of foreign technology and knowledge. Copyright © 2013 John Wiley & Sons, Ltd.