Populist parties in governments are on the rise in many European countries that are also major donors of foreign aid. While the general political development of populism has attracted much scientific and media attention, there is little knowledge about how populist parties influence foreign aid spending. Since radical right-wing populism tends to over-prioritize domestic politics, populist radical right-wing governments are likely to reduce foreign aid spending. We argue that the larger the share of populist radical right parties in a government is, the less foreign aid is spent. We account for divisions of power by distinguishing between populist radical right parties in the legislative and executive branches of government. Analysing 25 OECD countries between 1990 – 2016 using generalized additive models, we find empirical support for our hypotheses. Our findings on foreign aid have implications for understanding the impact of populist radical right- wing parties on foreign policy making more broadly.