This paper builds on recent generalisations of theory and empirics of comparative advantage and establishes the relative importance of different sources of comparative advantage in explaining trade, with particular focus on policy and institutional factors. The broad policy and institutional areas posited as determinants of comparative advantage in this paper include: physical capital, human capital (distinguishing between secondary, tertiary education and average years of schooling), financial development, energy supply, business climate, labour market institutions as well as import tariff policy. The empirical investigation is performed for bilateral trade of 55 OECD and selected emerging market (SEM) economies and 44 manufacturing sectors covering the entirety of merchandise trade. Our results show that comparative advantage remains an important determinant of trade and that it has changed over time, including as a result of changing policies and institutions. The policy and institutional areas shown to be important determinants of comparative advantage include physical and human capital accumulation (especially secondary and tertiary education), financial development, the business climate, as well as a number of aspects of labour market institutions. The results suggest also that comparative advantage has been — and is likely to be in the future — relatively more important for North-South and South-South trade. Overall, the results underscore the importance of a comprehensive approach to designing economic development policies, which should seek consistency between trade and other policy objectives.