With the gradual dismantling of tariffs and the growing integration of markets across countries, non-tariff and non-border barriers to international trade, investment and competition have become more visible, a greater source of trade tensions and costly with regard to the foregone global benefits of increased efficiency. In many OECD and non-OECD economies, market regulations were not designed with a view to their international ramifications, and domestic policies in the domain of trade, competition and investment, with few exceptions, take little account of international repercussions of non-border obstacles to the functioning of markets. Against this background, this paper examines the main issues underlying the current discussion of trade, investment and competition policy interactions, and the scope for further international co-operation ...