This research analyzes the determinants of voters’ attitudes towards protectionism in four Southeast Asian and Oceania countries (the Philippines, Thailand, Australia, and New Zealand) and discusses whether voters’ attitudes toward protectionism are related to their voting behavior. This study utilizes the endogenous trade policy formation theory in international economics to understand how voters’ attitudes toward protectionism are formed. Furthermore, by examining whether voters’ political party support can be explained by their attitudes toward protectionism, this study confirms that changes in each country’s trade policy orientation can be understood in the context of their domestic political-economic background. The main findings of this study are as follows: Voters in relatively labor-abundant countries such as the Philippines and Thailand prefer protectionist trade policies as their human capital attainment increases. In contrast, voters in relatively capital-abundant countries such as Australia and New Zealand prefer free trade policies as their human capital attainment increases. These findings align with the theoretical predictions of the Heckscher-Ohlin model-based factor endowment approach. However, since the factor endowment approach is based on the long-run assumption of free labor mobility across industries, it may deviate significantly from reality. To address this limitation, the analysis introduces a specific-factor approach that considers rigidities in the labor movement between industries to test whether there are differences in attitudes towards protectionism between voters in comparative advantage industries and voters in comparative disadvantage industries. The results of the analysis show that the theoretical predictions of the specific-factor approach did not have empirical validity for the voters in the four countries. Determining whether individual attitudes toward protectionist trade policies are associated with voting behavior requires a separate analysis. Analyzing the survey data on the party choices of each voter in general elections, the results show that their attitudes toward protectionism do not explain voters’ voting behavior in the Philippines and Thailand. In contrast, voters’ voting behavior in Australia and New Zealand is significantly explained by their attitudes toward protectionism. Australian voters who prefer higher trade barriers are more likely to support the right-wing populist party, the One Nation Party, while New Zealand voters who prefer higher trade barriers are more likely to support the Labour Party. From the above analysis, it can be concluded that trade policy orientations in Australia and New Zealand tend to reflect domestic political-economic backgrounds to a significant extent, while this is not the case in the Philippines and Thailand. As the estimation results of this study suggest, voting patterns in the Philippines and Thailand are strongly influenced by regionalist tendencies. This study concludes by emphasizing the need to refine trade negotiation strategies by taking into account the domestic political-economic situations of these four major trading partners of South Korea.