When does self-interest influence public opinion on contentious public policies? The bulk of theory in political science suggests that self-interest is only a minor force in public opinion. Using nationally representative survey data, we show how financial and spatial self-interest and partisanship all shape public opinion on opioid treatment policy. We find that a majority of respondents support a redistributive funding model for treatment programs, while treatment funded by taxation based on a community’s overdose rate is less popular. Moreover, financial self-interest cross-pressures lower-income Republicans, closing the partisan gap in support by more than half. We also experimentally test how the spatial burden of siting treatment clinics alters policy preferences. People across the political spectrum are less supportive when construction of a clinic is proposed closer to their home. These results highlight how partisanship and self-interest interact in shaping preferences on public policy with concentrated burdens.