The ‘learning-by-exporting’ hypothesis suggests that once a firm enters foreign markets, its productivity will increase thanks to exposure to knowledge and experience from abroad. Using Indonesia firm-level data for 2000–2012, this study scrutinises the effect of exporter learning on firm performance. I find that the exporter’s total factor productivity increases with exporting age, but not linearly. The effect is significant only until a certain year of exporting, and becomes insignificant thereafter. Relatively large exporters and those engaged in particular industries have clearer learning processes.