Many citizens feel excluded from political decision-making, which, in their eyes, is dominated by an unresponsive political elite. Citizens with high populist attitudes perceive the world through a populist ‘lens’ and therefore yearn for more popular control and for ‘the people’ to be included in the political process. Participatory budgeting should be particularly suited to address populist demands due to the fact that it is focused on giving citizens actual influence on policy-making. However, so far, no study has examined the effect of participation in a democratic innovation on populist attitudes. This paper empirically assesses if and to what extent participation in a participatory budget affects populist attitudes, and whether citizens with high populist attitudes are affected differently than citizens with low populist attitudes. We analyze panel data on participants of four local participatory budgeting events in the Netherlands before and after participation and find that citizens with high populist attitudes decrease these attitudes significantly after participating in a participatory budget, whereas citizens with low populist attitudes are not significantly affected. Moreover, the significant difference in change between these two groups suggests that citizens with high populist attitudes go ‘through the looking glass’ and become less populist after participating in a participatory budget.