AbstractWe use a multi‐country computable general equilibrium (CGE) model with agricultural policy details to simulate the effects of North American Free Trade Agreement (NAFTA). We find that Mexico gains from NAFTA only when it also removes domestic distortions in agriculture. In that case, agriculture can generate allocative efficiency gains large enough to offset the terms of trade losses that arise because Mexico has higher initial tariffs than its NAFTA partners. When an RTA forces a developing country to reform its domestic distortions that are linked to trade restrictions, it becomes a building block toward multilateralism.