With the continuous inflow of new immigrants, political participation of Latinos and Asian Americans has become increasingly important for understanding the American electoral politics. A few previous studies examining how political participation of Latinos and Asian Americans is contextually determined reported mixed empirical findings, and this paper re-examines the issue by considering how different features of racial contexts interact to influence the voting turnout of individual Latinos and Asian Americans. Theoretically, we present a model of turnout where a rational individual is motivated to participate, not only by individualistic benefits accrued to him-or herself, but also by perceptions of group-level benefitsconcerns regarding the welfare of other members of the racial group. We argue that racial contexts provide distinctive (dis-)incentives to participate, by influencing their perception of participatory benefits at the group level. Empirically, we find that the size of the group exerts a significant effect on turnout decisions of Latino and Asian American individuals, and, particularly for Latinos, its effect interacts with the economic status of the group and the overall racial heterogeneity in the county of residence.