This dissertation combines three empirical papers in International Trade and Labor Economics. The first chapter uses Ukrainian firm-level data to examine whether firms induced to import from the European Union by trade liberalization upgrade the quality of goods that they export. I use the instrumental variable regression to address the endogeneity of firms' import status. Obtained results confirm that new importers substantially improved the quality of products sold abroad. After splitting the sample into heterogeneous and homogeneous good producers, I found that the effect of importing is strong and statistically significant for the former and insignificant for the latter. The obtained results indicate that trade liberalization can ...