<p>This paper examines the effects of differences in sectoral compositions between countries on the liberalization of global tariffs in the coalition-proof Nash equilibrium sense. Using a static tariff-setting game with endogenous trade agreements, I develop a competing exporters model with three countries that differ in their sectoral compositions. I consider two settings that are differentiated by the type of trade agreements that countries can sign: free trade agreements (FTAs) and multilateral trade agreements, i.e., no FTAs. I study both symmetric and asymmetric differences in sectoral compositions across countries and find that, contrary to earlier results based on economic size asymmetries, FTAs act as stumbling blocks to the multilateral trading system when countries sufficiently differ in their sectoral compositions. This result is caused by the existence of a free riding incentive. Lastly, I show that permitting internal tariffs in FTAs typically strengthens the free riding incentive under symmetric sectoral differences, and in the asymmetric case may either mitigate or exacerbate the stumbling-block problem depending on countries’ sectoral compositions.</p>