Most trade agreements are ratified with overwhelming support by legislators throughout the world. This lack of opposition is surprising given the strong distributional consequences of trade and the expectation of conventional political economy theory that parliamentary votes on trade policy should be closely contested between winners and losers of globalization. To analyze the driving forces behind legislators’ voting behavior while avoiding the obscuring effect of party discipline, I analyze under which circumstances legislators decide to rebel against their party’s position when voting on the ratification of trade agreements. I put forward two hypotheses: First, rebellions are more likely when the trade agreement is with a larger trading partner and when the liberalization through the agreement is more comprehensive. Second, legislators will rebel when their party’s position does not align with their constituency’s economic interests. These hypotheses are supported by a series of multinomial regression analyses based on an original dataset comprising votes of several thousand legislators from multiple countries on the ratification of trade agreements.