This paper compares the degree of openness to trade of three developed countries markets—the European Union, Japan, the United States—with that of three middle-income countries, namely Brazil, India, and China. A theoretically consistent protection measure—the Mercantilistic Trade Restrictiveness Index (MTRI)—is employed to average tariffs at different levels of aggregation. The computation relies on a comparative static applied general equilibrium model (Global Trade Analysis Project—GTAP) featuring imperfect competition as well as on the bilateral applied tariffs included in the most recent version of the GTAP database. Results provide a different picture from what could have been expected given the widely publicized diffusion of preferential schemes supposedly favoring developing countries exports.