Partisan affective polarization describes the extent to which different partisans like or dislike each other. In Europe, affective dislike is strongest towards the radical-right, as mainstream voters tend to hold particularly negative affect towards radical-right supporters. This is an important pattern given the recent high levels of support for radical-right parties, for example in the Netherlands, France, and Italy. However, the perspective of radical-right supporters themselves has been largely neglected in existing work. To remedy this, we examine how radical-right supporters feel towards supporters of mainstream parties. We develop a new concept, dislike differentiation, which refers to the extent to which radical-right supporters differentiate in the dislike they harbor towards mainstream parties. We use two new studies that sampled 2,628 radical-right supporters in nine European polities. We find that some supporters reject all mainstream parties, whereas others follow more typical patterns of political competition along ideological lines. Dislike differentiation among radical-right supporters is linked to key socio-political phenomena, including party attachment, ideological extremism, satisfaction with democracy, and political tolerance. By creating a novel typology combining out-party dislike and dislike differentiation, we show that anti-system radical-right supporters, characterized by high out-party dislike and low dislike differentiation, are the least supportive of democracy. By centering our analysis on those voters that receive and radiate the highest levels of negative affect, we advance knowledge on what fosters polarized attitudes and intolerance in Europe’s multiparty systems in times when the electoral popularity of the radical-right is surging.