‘Learning by exporting’ refers to productivity gains experienced by firms after they commence exporting. Such gains are argued to be due to access to new knowledge and resources. This column explores some of the preconditions for learning-by-exporting effects, using data on the overseas activities and affiliations of Japanese firms. Firms that enter markets in which they don’t have affiliates or subsidiaries are found to enjoy the most learning-by-exporting productivity gains. These findings have implications for the timing of new market entry.