This paper examines whether firms that start exporting become more productive, controlling for the self-selection into export markets. Using micro data from Slovenian manufacturing firms from 1994 to 2000, the author employs matched sampling techniques and modifies the Olley and Pakes (1996) method to estimate total factor productivity, allowing for different market structures and relaxing the assumption that productivity follows an exogenous Markov process. The results show that export entrants become, on average, 8.8% more productive once they start exporting, with the productivity gap increasing to 12.4% after four years of exporting. These findings are robust to other controls such as private ownership. The analysis also reveals that productivity gains are higher for firms exporting only to high-income regions. The paper contributes by providing a methodology to analyze the causality from export status to productivity, controlling for self-selection, and testing the learning-by-exporting hypothesis.This paper examines whether firms that start exporting become more productive, controlling for the self-selection into export markets. Using micro data from Slovenian manufacturing firms from 1994 to 2000, the author employs matched sampling techniques and modifies the Olley and Pakes (1996) method to estimate total factor productivity, allowing for different market structures and relaxing the assumption that productivity follows an exogenous Markov process. The results show that export entrants become, on average, 8.8% more productive once they start exporting, with the productivity gap increasing to 12.4% after four years of exporting. These findings are robust to other controls such as private ownership. The analysis also reveals that productivity gains are higher for firms exporting only to high-income regions. The paper contributes by providing a methodology to analyze the causality from export status to productivity, controlling for self-selection, and testing the learning-by-exporting hypothesis.